fix: 修正行星事件边界与留点计算

- 统一 UT 事件时刻与 TT 查询时刻的边界判断
- 将外行星留点搜索锚定到对应冲日周期
- 修正水星、金星合日、留、大距事件选择
- 统一七大行星视位置计算辅助逻辑
- 增加公开 Last/Next 边界和 JPL/NAOJ 基线回归测试

README.en.md

@@ -46,7 +46,7 @@ go get b612.me/astro
 - Lunar position, rise/set, Earth distance, phase, new/full/quarter times, apparent diameter, bright-limb angle, parallactic angle, geocentric/topocentric libration, apsides, nodes, maximum declination
 - `lite/sun` and `lite/moon` lightweight approximation chains for watches, frontends, mini programs, and other resource-constrained environments
 - Global and local solar/lunar eclipses, solar central paths, partial footprints, visible local lunar eclipses, Saros metadata, and SVG diagrams
-- Seven major planets with positions, rise/set, conjunction/opposition/station events, quadratures, elongations, nodes, phase, apparent magnitude, apparent diameter, parallactic angle, and physical ephemerides
+- Seven major planets with positions, rise/set, conjunction/opposition/station events, quadratures, elongations, Mercury/Venus geocentric transits, nodes, phase, apparent magnitude, apparent diameter, parallactic angle, and physical ephemerides
 - 9100+ star catalog entries, constellation lookup, proper-motion propagation, rise/set, parallactic angle, and apparent altitude
 - Coordinate transforms, topocentric coordinates, sidereal time, precession, nutation, angular distance, refraction, airmass, parallactic angle, and Galactic coordinates
 - Standalone formulas for blackbody radiation, synodic periods, photometry, telescope limiting magnitude, stellar radius/temperature/luminosity relations, and airmass models
@@ -63,7 +63,7 @@ go get b612.me/astro
 | `moon` | Lunar position, rise/set, phases, new/full/quarter times, apparent altitude, parallactic angle, diameter, bright-limb angle, geocentric/topocentric libration, apsides, nodes, maximum declination |
 | `lite/sun` / `lite/moon` | Lightweight Sun/Moon approximation chains for minute-level rise/set, lightweight sky position, and lunar-phase work |
 | `eclipse` / `eclipse/svg` | Global/local solar and lunar eclipses, solar central paths, partial footprints, local visibility filtering, Saros metadata, SVG output |
-| `mercury` / `venus` | Positions, rise/set, conjunctions, stations, elongations, phase, parallactic angle, magnitude, diameter, nodes, physical ephemerides |
+| `mercury` / `venus` | Positions, rise/set, conjunctions, stations, elongations, geocentric transits, phase, parallactic angle, magnitude, diameter, nodes, physical ephemerides |
 | `mars` / `jupiter` / `saturn` / `uranus` / `neptune` | Positions, rise/set, conjunction/opposition, stations, quadratures, phase, parallactic angle, magnitude, diameter, nodes, physical ephemerides |
 | `earth` | Earth orbital eccentricity, perihelion, aphelion |
 | `star` | Constellation lookup, star catalog, proper motion / precession / nutation correction, stellar rise/set, parallactic angle, apparent altitude |
@@ -249,7 +249,6 @@ Output:
 
 ```text
 [魏明帝 景初三年腊月二十 蜀后主 延熙二年冬月十九 吴大帝 赤乌二年冬月二十] // one Gregorian instant maps to parallel Three Kingdoms lunisolar results
-
 [
   {
     "solarDate": "0240-01-01T08:08:08.000000008+08:00",
@@ -309,7 +308,6 @@ Output:
     "chineseZodiac": "羊"
   }
 ] // structured lunisolar records, one object per matching historical result
-
 1083-11-24 00:00:00 +0800 CST // Gregorian date corresponding to 元丰六年十月十二日
 [宋神宗 元丰六年十月十二 辽道宗 大康九年十月十二] // the same day also matches a Liao calendar result
 2026-02-17 00:00:00 +0800 CST // Chinese New Year in 2026
@@ -341,10 +339,10 @@ func main() {
 Output:
 
 ```text
-2020-02-04 17:03:17.820854187 +0800 CST // Beginning of Spring
-2020-12-21 18:02:17.568823993 +0800 CST // Winter Solstice
-2020-03-20 11:49:34.502393603 +0800 CST // March Equinox
-2020-03-20 11:49:34.502393603 +0800 CST // same result from direct longitude input
+2020-02-04 17:03:20.471614301 +0800 CST // Beginning of Spring
+2020-12-21 18:02:20.648710727 +0800 CST // Winter Solstice
+2020-03-20 11:49:37.149532735 +0800 CST // March Equinox
+2020-03-20 11:49:37.149532735 +0800 CST // same result from direct longitude input
 ```
 
 ### Sun And Moon
@@ -400,14 +398,14 @@ func main() {
 Output:
 
 ```text
-2020-01-01 07:22:27.964431345 +0800 CST <nil> // civil morning twilight begins
-2020-01-01 07:50:14.534510672 +0800 CST <nil> // sunrise
+2020-01-01 07:22:27.960488498 +0800 CST <nil> // civil morning twilight begins
+2020-01-01 07:50:14.530648291 +0800 CST <nil> // sunrise
 2020-01-01 12:47:35.933117866 +0800 CST // solar upper culmination
-2020-01-01 17:44:47.076647579 +0800 CST <nil> // sunset
-2020-01-01 18:12:33.629668056 +0800 CST <nil> // civil evening twilight ends
-2020-01-01 11:52:44.643359184 +0800 CST <nil> // moonrise
-2020-01-01 17:38:03.879639208 +0800 CST // lunar upper culmination
-2020-01-01 23:26:52.202896177 +0800 CST <nil> // moonset
+2020-01-01 17:44:47.070974707 +0800 CST <nil> // sunset
+2020-01-01 18:12:33.624035418 +0800 CST <nil> // civil evening twilight ends
+2020-01-01 11:52:45.157297253 +0800 CST <nil> // moonrise
+2020-01-01 17:38:02.510787248 +0800 CST // lunar upper culmination
+2020-01-01 23:26:51.580328643 +0800 CST <nil> // moonset
 ```
 
 #### Sun and Moon position
@@ -461,17 +459,16 @@ func main() {
 Output:
 
 ```text
-280.0152925179703 // apparent ecliptic longitude of the Sun, degrees
-23.436215552851408 // true obliquity of the ecliptic, degrees
-RA: 18h43m34.83s Dec: -23°3′30.25″ // apparent RA and Dec of the Sun
+280.01526210031136 // apparent ecliptic longitude of the Sun, degrees
+23.4362178391013 // true obliquity of the ecliptic, degrees
+RA: 18h43m34.82s Dec: -23°3′30.27″ // apparent RA and Dec of the Sun
 Sagittarius // English constellation containing the Sun
-Azimuth: 120.19483856399326 Altitude: 2.4014324584398516 Zenith: 87.59856754156014 // solar horizontal coordinates at Xi'an
-0.9832929365443133 // Sun-Earth distance, AU
-
-RA: 23h17m51.93s Dec: -10°19′17.02″ // topocentric apparent RA and Dec of the Moon
+Azimuth: 120.19477090015224 Altitude: 2.4014437419430097 Zenith: 87.59855625805699 // solar horizontal coordinates at Xi'an
+0.983292937163176 // Sun-Earth distance, AU
+RA: 23h17m53.15s Dec: -10°19′18.57″ // topocentric apparent RA and Dec of the Moon
 Aquarius // English constellation containing the Moon
-Azimuth: 67.84449893794012 Altitude: -45.13018696439911 Zenith: 135.13018696439912 // lunar horizontal coordinates at Xi'an
-404238.6354387698 // Earth-Moon distance, km
+Azimuth: 67.84050700509859 Altitude: -45.13425530765482 Zenith: 135.13425530765483 // lunar horizontal coordinates at Xi'an
+404238.6096080479 // Earth-Moon distance, km
 ```
 
 `sun.Physical` / `sun.PhysicalN` return:
@@ -609,12 +606,12 @@ func main() {
 Output:
 
 ```text
-0.3000437415436273 // about 30% of the lunar disk is illuminated
+0.300041309608744 // about 30% of the lunar disk is illuminated
 上峨眉月 // Chinese phase description
-2020-01-25 05:41:55.820311009 +0800 CST // next new moon
-2020-01-03 12:45:20.809730887 +0800 CST // next first quarter
-2020-01-11 03:21:14.729664623 +0800 CST // next full moon
-2020-01-17 20:58:20.955985486 +0800 CST // next last quarter
+2020-01-25 05:41:58.271192908 +0800 CST // next new moon
+2020-01-03 12:45:23.229190707 +0800 CST // next first quarter
+2020-01-11 03:21:17.159625291 +0800 CST // next full moon
+2020-01-17 20:58:23.396406769 +0800 CST // next last quarter
 ```
 
 Phase aliases:
@@ -674,6 +671,8 @@ Common entry points:
 - `LastSolarEclipse` / `NextSolarEclipse` / `ClosestSolarEclipse`: search global solar eclipses
 - `LocalSolarEclipseOnDate`: detect whether a site can see a local solar eclipse on that date
 - `LastLocalSolarEclipse` / `NextLocalSolarEclipse` / `ClosestLocalSolarEclipse`: search locally visible solar eclipses
+- `LastLocalTotalSolarEclipse` / `NextLocalTotalSolarEclipse` / `ClosestLocalTotalSolarEclipse`: search locally visible total solar eclipses, returning `(info, ok)`
+- `LastLocalAnnularSolarEclipse` / `NextLocalAnnularSolarEclipse` / `ClosestLocalAnnularSolarEclipse`: search locally visible annular solar eclipses, returning `(info, ok)`
 - `SolarEclipseCentralPath`: compute central line, northern/southern limits, and greatest-eclipse point
 - `SolarEclipsePartialFootprints`: compute the partial-eclipse penumbral footprint on Earth
 - `eclipse/svg.LocalSolarEclipseSVG`: render a local solar-disk SVG
@@ -925,6 +924,7 @@ Common entry points:
 - `LastLunarEclipse` / `NextLunarEclipse` / `ClosestLunarEclipse`: search global lunar eclipses
 - `LocalLunarEclipseOnDate`: detect whether a visible lunar eclipse is visible from a site on a local date
 - `LastLocalLunarEclipse` / `NextLocalLunarEclipse` / `ClosestLocalLunarEclipse`: search visible local lunar eclipses
+- `LastLocalTotalLunarEclipse` / `NextLocalTotalLunarEclipse` / `ClosestLocalTotalLunarEclipse`: search visible local total lunar eclipses, returning `(info, ok)`
 - `GeometricLocalLunarEclipseOnDate`: detect geometric lunar eclipse overlap without filtering by whether the Moon is above the horizon
 - `eclipse/svg.LunarEclipseSVG`: render a lunar-eclipse shadow-path SVG
 
@@ -1002,18 +1002,18 @@ Output:
 ```text
 total // eclipse type
 true {125 49 72} // Lunar Saros 125, member 49/72
-2028-12-31 16:52:05.257715537 +0000 UTC // greatest eclipse
-2.273989043 1.246114288 // penumbral and umbral magnitudes
-2028-12-31 14:03:54.163612125 +0000 UTC // P1
-2028-12-31 15:07:42.293254197 +0000 UTC // U1
-2028-12-31 16:16:27.717077732 +0000 UTC // U2
-2028-12-31 17:27:46.687390804 +0000 UTC // U3
-2028-12-31 18:36:32.272528112 +0000 UTC // U4
-2028-12-31 19:40:11.173523784 +0000 UTC // P4
-2.29960334 1.25117109 // Chauvenet penumbral and umbral magnitudes
+2028-12-31 16:52:05.566135346 +0000 UTC // greatest eclipse
+2.273989043382249 1.2461142882946992 // penumbral and umbral magnitudes
+2028-12-31 14:03:54.219463169 +0000 UTC // P1
+2028-12-31 15:07:42.115980684 +0000 UTC // U1
+2028-12-31 16:16:27.24464178 +0000 UTC // U2
+2028-12-31 17:27:46.214954853 +0000 UTC // U3
+2028-12-31 18:36:32.251235246 +0000 UTC // U4
+2028-12-31 19:40:11.52023971 +0000 UTC // P4
+2.2996033397593934 1.2511710895700923 // Chauvenet penumbral and umbral magnitudes
 true // local date overlaps an eclipse
 total // local eclipse type
-2029-01-01 00:52:05.257715537 +0800 CST // greatest eclipse in UTC+8
+2029-01-01 00:52:05.566135346 +0800 CST // greatest eclipse in UTC+8
 ```
 
 #### Checks against NASA data
@@ -1153,20 +1153,20 @@ func main() {
 Output:
 
 ```text
-2019-11-11 23:21:39.702344834 +0800 CST // previous inferior conjunction of Mercury
-2021-03-26 14:57:38.289429545 +0800 CST // next superior conjunction of Venus
-2019-11-01 04:31:47.807287573 +0800 CST // previous Mercury station from prograde to retrograde
-2021-12-18 18:59:12.762369811 +0800 CST // next Venus station from retrograde to prograde
-2019-10-20 11:59:33.893027007 +0800 CST // previous greatest eastern elongation of Mercury
-2020-08-13 07:56:02.326616048 +0800 CST // next greatest western elongation of Venus
-2020-01-01 10:01:10.821288228 +0800 CST <nil> // Venus rise time in Xi'an; no error
-2020-01-01 20:27:00.741534233 +0800 CST <nil> // Venus set time in Xi'an; no error
+2019-11-11 23:21:42.048057317 +0800 CST // previous inferior conjunction of Mercury
+2021-03-26 14:57:43.01215589 +0800 CST // next superior conjunction of Venus
+2019-11-01 04:31:38.999851942 +0800 CST // previous Mercury station from prograde to retrograde
+2020-06-25 02:07:41.549940705 +0800 CST // next Venus station from retrograde to prograde
+2019-10-20 11:50:28.734245896 +0800 CST // previous greatest eastern elongation of Mercury
+2020-08-13 07:59:17.123789191 +0800 CST // next greatest western elongation of Venus
+2020-01-01 10:02:34.172194004 +0800 CST <nil> // Venus rise time in Xi'an; no error
+2020-01-01 20:25:37.363712489 +0800 CST <nil> // Venus set time in Xi'an; no error
 -4 // Venus apparent magnitude
 49.98145049145023 // Venus phase angle, degrees
 0.8215177914415865 // illuminated fraction of Venus
-255.63802111818407 // bright-limb position angle of Venus, degrees
-1.2760033106813273 // Earth-Venus distance, AU
-0.7262288470390035 // Sun-Venus distance, AU
+255.63802093000768 // bright-limb position angle of Venus, degrees
+1.2778819631550336 // Earth-Venus distance, AU
+0.7262651056423838 // Sun-Venus distance, AU
 ```
 
 Inner and outer planets also expose `Diameter` / `Semidiameter` and `N` variants, returning geocentric apparent diameter/semidiameter in arcseconds.
@@ -1191,6 +1191,67 @@ For `date := 2020-01-01 08:08:08 CST`, the output is:
 76.86008484515058 256.8600848451506 // Venus ascending-node and descending-node longitudes, degrees
 ```
 
+Mercury and Venus also expose `NextTransit` / `LastTransit` / `ClosestTransit` for geocentric planetary transits. "Geocentric" means the planet disk crosses the solar disk as seen from Earth's center; it does not test whether the Sun is above the horizon at a particular observing site. For observing plans, combine this with local solar altitude and weather.
+
+```go
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"b612.me/astro/mercury"
+	"b612.me/astro/venus"
+)
+
+func main() {
+	// Next geocentric Mercury transit after the beginning of 2019.
+	mercuryTransit := mercury.NextTransit(time.Date(2019, 1, 1, 0, 0, 0, 0, time.UTC))
+	fmt.Println(mercuryTransit.Valid)
+	fmt.Println(mercuryTransit.Start)
+	fmt.Println(mercuryTransit.InternalStart)
+	fmt.Println(mercuryTransit.Greatest)
+	fmt.Println(mercuryTransit.InternalEnd)
+	fmt.Println(mercuryTransit.End)
+	fmt.Println(mercuryTransit.Duration)
+	fmt.Println(mercuryTransit.MinimumSeparationArcsec)
+	fmt.Println(mercuryTransit.SunSemidiameterArcsec)
+	fmt.Println(mercuryTransit.PlanetSemidiameterArcsec)
+
+	// Next geocentric Venus transit after the beginning of 2012.
+	venusTransit := venus.NextTransit(time.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC))
+	fmt.Println(venusTransit.Valid)
+	fmt.Println(venusTransit.Start)
+	fmt.Println(venusTransit.InternalStart)
+	fmt.Println(venusTransit.Greatest)
+	fmt.Println(venusTransit.InternalEnd)
+	fmt.Println(venusTransit.End)
+	fmt.Println(venusTransit.Duration)
+}
+```
+
+Output:
+
+```text
+true // a valid geocentric Mercury transit was found
+2019-11-11 12:35:31.617325544 +0000 UTC // first contact: Mercury externally enters the solar disk
+2019-11-11 12:37:13.078211545 +0000 UTC // second contact: Mercury is fully inside the solar disk
+2019-11-11 15:19:48.410291075 +0000 UTC // greatest transit: Mercury center is closest to the Sun center
+2019-11-11 18:02:29.2267102 +0000 UTC // third contact: Mercury starts leaving the solar disk
+2019-11-11 18:04:10.687676668 +0000 UTC // fourth contact: Mercury externally leaves the solar disk
+5h28m39.070351124s // geocentric transit duration from first to fourth contact
+75.92506897631685 // minimum Mercury-Sun center separation at greatest transit, arcseconds
+968.8881520858397 // solar semidiameter at greatest transit, arcseconds
+4.978442860728242 // Mercury semidiameter at greatest transit, arcseconds
+true // a valid geocentric Venus transit was found
+2012-06-05 22:09:47.514281272 +0000 UTC // first contact: Venus externally enters the solar disk
+2012-06-05 22:27:35.701768398 +0000 UTC // second contact: Venus is fully inside the solar disk
+2012-06-06 01:29:35.408823788 +0000 UTC // greatest transit: Venus center is closest to the Sun center
+2012-06-06 04:31:34.90493685 +0000 UTC // third contact: Venus starts leaving the solar disk
+2012-06-06 04:49:23.303366303 +0000 UTC // fourth contact: Venus externally leaves the solar disk
+6h39m35.789085031s // geocentric transit duration from first to fourth contact
+```
+
 #### Outer planets
 
 ```go
@@ -1251,18 +1312,18 @@ func main() {
 Output:
 
 ```text
-2020-10-14 07:25:47.740884125 +0800 CST // next opposition of Mars
-2021-01-29 09:39:30.916356146 +0800 CST // next conjunction of Jupiter
-2019-04-30 10:28:27.453395426 +0800 CST // previous Saturn station from prograde to retrograde
-saturn B=23.577026 Bp=23.266930 P=6.629811 dU=1.171017 major=34.133852 minor=13.652911 // Saturn ring B, B', P, dU, major axis, minor axis
-2021-01-14 21:35:01.269377768 +0800 CST // next Uranus station from retrograde to prograde
-2019-12-08 17:00:13.772284984 +0800 CST // previous eastern quadrature of Neptune
-2020-06-07 03:10:57.179121673 +0800 CST // next western quadrature of Mars
-2020-01-01 04:40:05.409269034 +0800 CST <nil> // Mars rise time in Xi'an; no error
-2020-01-01 14:56:57.175483703 +0800 CST <nil> // Mars set time in Xi'an; no error
+2020-10-14 07:25:50.262777507 +0800 CST // next opposition of Mars
+2021-01-29 09:39:33.565426468 +0800 CST // next conjunction of Jupiter
+2019-04-30 10:27:41.606289446 +0800 CST // previous Saturn station from prograde to retrograde
+saturn B=23.577026 Bp=23.266930 P=6.629811 dU=1.171016 major=34.133852 minor=13.652911 // Saturn ring B, B', P, dU, major axis, minor axis
+2020-01-11 15:23:07.378419935 +0800 CST // next Uranus station from retrograde to prograde
+2019-12-08 17:00:15.328663587 +0800 CST // previous eastern quadrature of Neptune
+2020-06-07 03:10:59.356176853 +0800 CST // next western quadrature of Mars
+2020-01-01 04:41:29.622089266 +0800 CST <nil> // Mars rise time in Xi'an; no error
+2020-01-01 14:55:32.963870465 +0800 CST <nil> // Mars set time in Xi'an; no error
 1.57 // Mars apparent magnitude
-2.1820316323604088 // Earth-Mars distance, AU
-1.5894169865107062 // Sun-Mars distance, AU
+2.1844284956325937 // Earth-Mars distance, AU
+1.5897860004265403 // Sun-Mars distance, AU
 ```
 
 `saturn.Ring` returns `RingInfo`: `EarthLatitude` is ring opening angle B, `SunLatitude` is B', `PositionAngle` is the position angle of the northern semiminor axis, `DeltaU` is the Saturnicentric longitude difference between the Sun and Earth in the ring plane, and `MajorAxis` / `MinorAxis` are the apparent outer major/minor axes in arcseconds.
@@ -1312,7 +1373,7 @@ Output:
 
 ```text
 jupiter DS=54.342153 DE=1.436485 CMI=292.712909 CMII=276.309048 CMIII=147.241811 // Jupiter DS/DE and System I/II/III central meridians, degrees
-saturn B=-0.608048 Bp=-2.675677 P=4.480276 major=42.709920 minor=0.453248 // Saturn ring B, B', minor-axis position angle, outer major/minor axes
+saturn B=-0.608046 Bp=-2.675677 P=4.480276 major=42.709920 minor=0.453246 // Saturn ring B, B', minor-axis position angle, outer major/minor axes
 ```
 
 If only Jupiter central meridians are needed:
@@ -1475,8 +1536,8 @@ Output:
 2019-12-31 19:22:56.176710426 +0800 CST // rise time of Sirius
 2020-01-01 05:30:39.834894239 +0800 CST // set time of Sirius
 Canis Major // English constellation containing Sirius
-5h58m10.19s // right ascension of Vega in year 13600
-84°19′26.25″ // declination of Vega in year 13600
+5h58m5.71s // right ascension of Vega in year 13600
+84°19′26.13″ // declination of Vega in year 13600
 天狼 Sirius -1.46 // first brightest-star entry: Chinese name, common English name, apparent magnitude
 ```
 
@@ -1767,7 +1828,7 @@ Notes:
 - `lite/sun` and `lite/moon` lightweight Sun/Moon chains for minute-level rise/set, lightweight position, and lunar-phase work
 - Earth eccentricity, Sun-Earth distance, perihelion, aphelion
 - Apparent/mean sidereal time, constellation lookup, common coordinate transforms, refraction, airmass, parallactic angle, Galactic coordinates
-- Seven major-planet coordinates, Sun/body and Earth/body distances, special events, physical ephemerides, apparent diameters, phases, parallactic angles, and nodes
+- Seven major-planet coordinates, Sun/body and Earth/body distances, special events, Mercury/Venus geocentric transits, physical ephemerides, apparent diameters, phases, parallactic angles, and nodes
 - Chinese lunisolar calendar conversion from 104 BCE to 3000 CE
 - 9100+ star catalog
 - Generic small-body orbit propagation, H-G apparent magnitude, visual-binary position angle and separation

README.md

@@ -44,7 +44,7 @@ go get b612.me/astro
 - 🌙 **月亮计算**：天球位置、月出月落、地月距离、月相、朔望时间、视直径、亮边位置角、视差角、地心/站心天平动、近远地点、交点、最大赤纬等
 - 🪶 **轻量链路**：`lite/sun` 与 `lite/moon` 提供面向手表、前端、小程序和其它资源受限环境的轻量近似太阳/月亮算法，覆盖天球位置、升落和月相
 - 🌗 **日月食**：全局日食、站心日食、中心线/偏食足迹、月食、地方可见月食与 SVG 示意图
-- 🪐 **行星计算**：七大行星天球位置、升落时间、合冲留等特殊天象时间、升交点/降交点、视直径/视半径、相位、视差角、节点、视星等与物理星历
+- 🪐 **行星计算**：七大行星天球位置、升落时间、合冲留、大距、水星/金星地心凌日等特殊天象时间、升交点/降交点、视直径/视半径、相位、视差角、节点、视星等与物理星历
 - ⭐ **恒星计算**：指定天球坐标所属星座；同时包含9100颗恒星数据库，可计算升降时间、视差角和视高度角，获取指定日期的恒星坐标信息
 - 🧭 **坐标工具**：黄道/赤道/地平坐标转换、站心坐标、恒星时、岁差、章动、角距离、大气折射、大气质量、视差角、银道坐标
 - 🔭 **研究公式**：黑体辐射、会合周期、星等距离换算、望远镜极限星等、恒星半径/温度/光度换算、大气质量模型
@@ -61,7 +61,7 @@ go get b612.me/astro
 | `moon` | 月亮位置、月出月落、月相、朔望弦、视高度角、视差角、视直径、亮边位置角、地心/站心天平动、近远地点、交点、最大赤纬 |
 | `lite/sun` / `lite/moon` | 轻量太阳/月亮近似链路，面向分钟级升落、轻量天球位置和月相计算 |
 | `eclipse` / `eclipse/svg` | 全局/局地日月食、日食中心线与偏食足迹、局地可见性筛选、日月食 SVG |
-| `mercury` / `venus` | 水星、金星位置、升落、合日、留、大距、相位、视差角、视星等、视直径、节点和物理星历 |
+| `mercury` / `venus` | 水星、金星位置、升落、合日、留、大距、地心凌日、相位、视差角、视星等、视直径、节点和物理星历 |
 | `mars` / `jupiter` / `saturn` / `uranus` / `neptune` | 外行星位置、升落、合冲、留、方照、相位、视差角、视星等、视直径、节点和物理星历 |
 | `earth` | 地球轨道偏心率、近日点、远日点 |
 | `star` | 星座判定、恒星数据库、恒星自行/岁差/章动修正、恒星升落、视差角、视高度角 |
@@ -309,7 +309,6 @@ func main() {
 ```text
 // 同一公历时刻在三国并立时期会映射到多个政权各自的农历结果
 [魏明帝 景初三年腊月二十 蜀后主 延熙二年冬月十九 吴大帝 赤乌二年冬月二十]
-
 // 结构化农历信息输出；每个对象对应一个政权口径下的结果
 [
   {
@@ -370,14 +369,12 @@ func main() {
     "chineseZodiac": "羊"
   }
 ]
-
 // “元丰六年十月十二日”对应的公历日期
 1083-11-24 00:00:00 +0800 CST
 // 同一天在并行政权下还会命中辽道宗大康九年十月十二
 [宋神宗 元丰六年十月十二 辽道宗 大康九年十月十二]
-
 // 现代农历日期转换结果；2026 年正月初一对应 2026-02-17
-2026-02-17 00:00:00 +0800 CST //2026年春节
+2026-02-17 00:00:00 +0800 CST
 ```
 
 #### 节气
@@ -407,10 +404,10 @@ func main() {
 输出结果
 
 ```
-2020-02-04 17:03:17.820854187 +0800 CST
-2020-12-21 18:02:17.568823993 +0800 CST
-2020-03-20 11:49:34.502393603 +0800 CST
-2020-03-20 11:49:34.502393603 +0800 CST
+2020-02-04 17:03:20.471614301 +0800 CST
+2020-12-21 18:02:20.648710727 +0800 CST
+2020-03-20 11:49:37.149532735 +0800 CST
+2020-03-20 11:49:37.149532735 +0800 CST
 
 ```
 
@@ -474,14 +471,14 @@ func main() {
 输出结果
 
 ```
-2020-01-01 07:22:27.964431345 +0800 CST <nil>
-2020-01-01 07:50:14.534510672 +0800 CST <nil>
+2020-01-01 07:22:27.960488498 +0800 CST <nil>
+2020-01-01 07:50:14.530648291 +0800 CST <nil>
 2020-01-01 12:47:35.933117866 +0800 CST
-2020-01-01 17:44:47.076647579 +0800 CST <nil>
-2020-01-01 18:12:33.629668056 +0800 CST <nil>
-2020-01-01 11:52:44.643359184 +0800 CST <nil>
-2020-01-01 17:38:03.879639208 +0800 CST
-2020-01-01 23:26:52.202896177 +0800 CST <nil>
+2020-01-01 17:44:47.070974707 +0800 CST <nil>
+2020-01-01 18:12:33.624035418 +0800 CST <nil>
+2020-01-01 11:52:45.157297253 +0800 CST <nil>
+2020-01-01 17:38:02.510787248 +0800 CST
+2020-01-01 23:26:51.580328643 +0800 CST <nil>
 
 
 ```
@@ -536,17 +533,16 @@ func main() {
 输出结果：
 
 ```
-280.0152925179703
-23.436215552851408
-赤经： 18h43m34.83s 赤纬： -23°3′30.25″
+280.01526210031136
+23.4362178391013
+赤经： 18h43m34.82s 赤纬： -23°3′30.27″
 人马座
-方位角： 120.19483856399326 高度角： 2.4014324584398516 天顶距： 87.59856754156014
-0.9832929365443133
-
-赤经： 23h17m51.93s 赤纬： -10°19′17.02″
+方位角： 120.19477090015224 高度角： 2.4014437419430097 天顶距： 87.59855625805699
+0.983292937163176
+赤经： 23h17m53.15s 赤纬： -10°19′18.57″
 宝瓶座
-方位角： 67.84449893794012 高度角： -45.13018696439911 天顶距： 135.13018696439912
-404238.6354387698
+方位角： 67.84050700509859 高度角： -45.13425530765482 天顶距： 135.13425530765483
+404238.6096080479
 ```
 
 太阳还提供 `sun.Physical` / `sun.PhysicalN`，返回：
@@ -683,12 +679,12 @@ func main() {
 输出结果：
 
 ```
-0.3000437415436273 // 月面约有 30% 被太阳照亮
+0.300041309608744 // 月面约有 30% 被太阳照亮
 上峨眉月 // 当前月相描述
-2020-01-25 05:41:55.820311009 +0800 CST // 下一次朔月
-2020-01-03 12:45:20.809730887 +0800 CST // 下一次上弦
-2020-01-11 03:21:14.729664623 +0800 CST // 下一次望月，也就是满月
-2020-01-17 20:58:20.955985486 +0800 CST // 下一次下弦
+2020-01-25 05:41:58.271192908 +0800 CST // 下一次朔月
+2020-01-03 12:45:23.229190707 +0800 CST // 下一次上弦
+2020-01-11 03:21:17.159625291 +0800 CST // 下一次望月，也就是满月
+2020-01-17 20:58:23.396406769 +0800 CST // 下一次下弦
 ```
 
 月相四个相位同时提供拼音名和英文 alias，例如：
@@ -742,6 +738,8 @@ func main() {
 - `LastSolarEclipse` / `NextSolarEclipse` / `ClosestSolarEclipse`：搜索全局日食
 - `LocalSolarEclipseOnDate`：判断某地当天是否能看到站心日食
 - `LastLocalSolarEclipse` / `NextLocalSolarEclipse` / `ClosestLocalSolarEclipse`：搜索某地可见的站心日食
+- `LastLocalTotalSolarEclipse` / `NextLocalTotalSolarEclipse` / `ClosestLocalTotalSolarEclipse`：搜索某地可见的日全食，返回 `(info, ok)`
+- `LastLocalAnnularSolarEclipse` / `NextLocalAnnularSolarEclipse` / `ClosestLocalAnnularSolarEclipse`：搜索某地可见的日环食，返回 `(info, ok)`
 - `SolarEclipseCentralPath`：计算中心线、南北界和食甚点
 - `SolarEclipsePartialFootprints`：计算偏食半影在地球表面的足迹
 - `eclipse/svg.LocalSolarEclipseSVG`：生成某地的日面视圆 SVG
@@ -995,6 +993,7 @@ true 13424 // 北京日全食 SVG 生成成功，长度 13424 字节
 - `LastLunarEclipse` / `NextLunarEclipse` / `ClosestLunarEclipse`：搜索全局月食
 - `LocalLunarEclipseOnDate`：判断某地当天是否能看到可见月食
 - `LastLocalLunarEclipse` / `NextLocalLunarEclipse` / `ClosestLocalLunarEclipse`：搜索某地可见月食
+- `LastLocalTotalLunarEclipse` / `NextLocalTotalLunarEclipse` / `ClosestLocalTotalLunarEclipse`：搜索某地可见月全食，返回 `(info, ok)`
 - `GeometricLocalLunarEclipseOnDate`：判断某地当天是否发生几何月食，不做“月亮在地平线上方”的可见性过滤
 - `eclipse/svg.LunarEclipseSVG`：生成月食穿影图 SVG
 
@@ -1071,18 +1070,18 @@ func main() {
 ```text
 total
 true {125 49 72}
-2028-12-31 16:52:05.257715537 +0000 UTC
-2.273989043 1.246114288
-2028-12-31 14:03:54.163612125 +0000 UTC
-2028-12-31 15:07:42.293254197 +0000 UTC
-2028-12-31 16:16:27.717077732 +0000 UTC
-2028-12-31 17:27:46.687390804 +0000 UTC
-2028-12-31 18:36:32.272528112 +0000 UTC
-2028-12-31 19:40:11.173523784 +0000 UTC
-2.29960334 1.25117109
+2028-12-31 16:52:05.566135346 +0000 UTC
+2.273989043382249 1.2461142882946992
+2028-12-31 14:03:54.219463169 +0000 UTC
+2028-12-31 15:07:42.115980684 +0000 UTC
+2028-12-31 16:16:27.24464178 +0000 UTC
+2028-12-31 17:27:46.214954853 +0000 UTC
+2028-12-31 18:36:32.251235246 +0000 UTC
+2028-12-31 19:40:11.52023971 +0000 UTC
+2.2996033397593934 1.2511710895700923
 true
 total
-2029-01-01 00:52:05.257715537 +0800 CST
+2029-01-01 00:52:05.566135346 +0800 CST
 ```
 
 ##### 与 NASA 数据对照
@@ -1229,20 +1228,20 @@ func main() {
 输出结果：
 
 ```
-2019-11-11 23:21:39.702344834 +0800 CST // 水星上次下合
-2021-03-26 14:57:38.289429545 +0800 CST // 金星下次上合
-2019-11-01 04:31:47.807287573 +0800 CST // 水星上次由顺行转逆行的留
-2021-12-18 18:59:12.762369811 +0800 CST // 金星下次由逆行转顺行的留
-2019-10-20 11:59:33.893027007 +0800 CST // 水星上次东大距
-2020-08-13 07:56:02.326616048 +0800 CST // 金星下次西大距
-2020-01-01 10:01:10.821288228 +0800 CST <nil> // 西安当天金星升起时刻；无错误
-2020-01-01 20:27:00.741534233 +0800 CST <nil> // 西安当天金星落下时刻；无错误
+2019-11-11 23:21:42.048057317 +0800 CST // 水星上次下合
+2021-03-26 14:57:43.01215589 +0800 CST // 金星下次上合
+2019-11-01 04:31:38.999851942 +0800 CST // 水星上次由顺行转逆行的留
+2020-06-25 02:07:41.549940705 +0800 CST // 金星下次由逆行转顺行的留
+2019-10-20 11:50:28.734245896 +0800 CST // 水星上次东大距
+2020-08-13 07:59:17.123789191 +0800 CST // 金星下次西大距
+2020-01-01 10:02:34.172194004 +0800 CST <nil> // 西安当天金星升起时刻；无错误
+2020-01-01 20:25:37.363712489 +0800 CST <nil> // 西安当天金星落下时刻；无错误
 -4 // 金星视星等
 49.98145049145023 // 金星相位角，单位度
 0.8215177914415865 // 金星被照亮比例
-255.63802111818407 // 金星亮面中心位置角，单位度
-1.2760033106813273 // 金地距离，单位 AU
-0.7262288470390035 // 金日距离，单位 AU
+255.63802093000768 // 金星亮面中心位置角，单位度
+1.2778819631550336 // 金地距离，单位 AU
+0.7262651056423838 // 金日距离，单位 AU
 ```
 
 内外行星同样提供 `Diameter` / `Semidiameter`（以及 `N` 版），返回地心视直径/视半径，单位为角秒。
@@ -1267,6 +1266,67 @@ fmt.Println(venus.AscendingNode(date), venus.DescendingNode(date))
 76.86008484515058 256.8600848451506 // 金星升交点、降交点黄经，单位度
 ```
 
+水星和金星还提供 `NextTransit` / `LastTransit` / `ClosestTransit` 地心凌日查询。这里的“地心”指从地球中心看到的行星圆面经过太阳圆面，不判断某个地点当时太阳是否在地平线上；如果要做观测计划，还需要结合本地太阳高度角和天气条件。
+
+```go
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"b612.me/astro/mercury"
+	"b612.me/astro/venus"
+)
+
+func main() {
+	// 查询 2019 年之后下一次地心水星凌日。
+	mercuryTransit := mercury.NextTransit(time.Date(2019, 1, 1, 0, 0, 0, 0, time.UTC))
+	fmt.Println(mercuryTransit.Valid)
+	fmt.Println(mercuryTransit.Start)
+	fmt.Println(mercuryTransit.InternalStart)
+	fmt.Println(mercuryTransit.Greatest)
+	fmt.Println(mercuryTransit.InternalEnd)
+	fmt.Println(mercuryTransit.End)
+	fmt.Println(mercuryTransit.Duration)
+	fmt.Println(mercuryTransit.MinimumSeparationArcsec)
+	fmt.Println(mercuryTransit.SunSemidiameterArcsec)
+	fmt.Println(mercuryTransit.PlanetSemidiameterArcsec)
+
+	// 查询 2012 年之后下一次地心金星凌日。
+	venusTransit := venus.NextTransit(time.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC))
+	fmt.Println(venusTransit.Valid)
+	fmt.Println(venusTransit.Start)
+	fmt.Println(venusTransit.InternalStart)
+	fmt.Println(venusTransit.Greatest)
+	fmt.Println(venusTransit.InternalEnd)
+	fmt.Println(venusTransit.End)
+	fmt.Println(venusTransit.Duration)
+}
+```
+
+输出结果：
+
+```text
+true // 找到一次有效的地心水星凌日
+2019-11-11 12:35:31.617325544 +0000 UTC // 一触：水星外切进入太阳圆面
+2019-11-11 12:37:13.078211545 +0000 UTC // 二触：水星完全进入太阳圆面
+2019-11-11 15:19:48.410291075 +0000 UTC // 凌甚：水星中心最接近太阳中心
+2019-11-11 18:02:29.2267102 +0000 UTC // 三触：水星开始离开太阳圆面
+2019-11-11 18:04:10.687676668 +0000 UTC // 四触：水星外切离开太阳圆面
+5h28m39.070351124s // 一触到四触的地心凌日持续时间
+75.92506897631685 // 凌甚时水星中心与太阳中心的最小角距离，单位角秒
+968.8881520858397 // 凌甚时太阳视半径，单位角秒
+4.978442860728242 // 凌甚时水星视半径，单位角秒
+true // 找到一次有效的地心金星凌日
+2012-06-05 22:09:47.514281272 +0000 UTC // 一触：金星外切进入太阳圆面
+2012-06-05 22:27:35.701768398 +0000 UTC // 二触：金星完全进入太阳圆面
+2012-06-06 01:29:35.408823788 +0000 UTC // 凌甚：金星中心最接近太阳中心
+2012-06-06 04:31:34.90493685 +0000 UTC // 三触：金星开始离开太阳圆面
+2012-06-06 04:49:23.303366303 +0000 UTC // 四触：金星外切离开太阳圆面
+6h39m35.789085031s // 一触到四触的地心凌日持续时间
+```
+
 #### 外行星
 
 ```go
@@ -1326,18 +1386,18 @@ func main() {
 输出结果：
 
 ```
-2020-10-14 07:25:47.740884125 +0800 CST // 火星下次冲日
-2021-01-29 09:39:30.916356146 +0800 CST // 木星下次合日
-2019-04-30 10:28:27.453395426 +0800 CST // 土星上次由顺行转逆行的留
-saturn B=23.577026 Bp=23.266930 P=6.629811 dU=1.171017 major=34.133852 minor=13.652911 // 土星环 B、B'、P、dU、长轴、短轴
-2021-01-14 21:35:01.269377768 +0800 CST // 天王星下次由逆行转顺行的留
-2019-12-08 17:00:13.772284984 +0800 CST // 海王星上次东方照
-2020-06-07 03:10:57.179121673 +0800 CST // 火星下次西方照
-2020-01-01 04:40:05.409269034 +0800 CST <nil> // 西安当天火星升起时刻；无错误
-2020-01-01 14:56:57.175483703 +0800 CST <nil> // 西安当天火星落下时刻；无错误
+2020-10-14 07:25:50.262777507 +0800 CST // 火星下次冲日
+2021-01-29 09:39:33.565426468 +0800 CST // 木星下次合日
+2019-04-30 10:27:41.606289446 +0800 CST // 土星上次由顺行转逆行的留
+saturn B=23.577026 Bp=23.266930 P=6.629811 dU=1.171016 major=34.133852 minor=13.652911 // 土星环 B、B'、P、dU、长轴、短轴
+2020-01-11 15:23:07.378419935 +0800 CST // 天王星下次由逆行转顺行的留
+2019-12-08 17:00:15.328663587 +0800 CST // 海王星上次东方照
+2020-06-07 03:10:59.356176853 +0800 CST // 火星下次西方照
+2020-01-01 04:41:29.622089266 +0800 CST <nil> // 西安当天火星升起时刻；无错误
+2020-01-01 14:55:32.963870465 +0800 CST <nil> // 西安当天火星落下时刻；无错误
 1.57 // 火星视星等
-2.1820316323604088 // 地火距离，单位 AU
-1.5894169865107062 // 日火距离，单位 AU
+2.1844284956325937 // 地火距离，单位 AU
+1.5897860004265403 // 日火距离，单位 AU
 
 ```
 
@@ -1388,7 +1448,7 @@ func main() {
 
 ```text
 jupiter DS=54.342153 DE=1.436485 CMI=292.712909 CMII=276.309048 CMIII=147.241811 // 木星子日/子地赤纬，System I/II/III 中央经线，单位度
-saturn B=-0.608048 Bp=-2.675677 P=4.480276 major=42.709920 minor=0.453248 // 土星环 B、B'、短轴位置角、外缘长短轴，角度单位度，长短轴单位角秒
+saturn B=-0.608046 Bp=-2.675677 P=4.480276 major=42.709920 minor=0.453246 // 土星环 B、B'、短轴位置角、外缘长短轴，角度单位度，长短轴单位角秒
 ```
 
 只需要中央经线时，可以单独调用 `CentralMeridians`：
@@ -1555,8 +1615,8 @@ func main() {
 2019-12-31 19:22:56.176710426 +0800 CST // 天狼星升起时刻
 2020-01-01 05:30:39.834894239 +0800 CST // 天狼星落下时刻
 大犬座 // 天狼星所在星座
-5h58m10.19s // 织女一在公元 13600 年的赤经
-84°19′26.25″ // 织女一在公元 13600 年的赤纬
+5h58m5.71s // 织女一在公元 13600 年的赤经
+84°19′26.13″ // 织女一在公元 13600 年的赤纬
 天狼 Sirius -1.46 // 最亮恒星表第一项：中文名、英文常用名、视星等
 ```
 
@@ -1849,7 +1909,7 @@ func main() {
 - ✅ `lite/sun`、`lite/moon` 轻量太阳/月亮链路：面向分钟级升落、轻量位置和月相计算
 - ✅ 地球偏心率、日地距离、近日点、远日点
 - ✅ 真平恒星时、星座计算、常用坐标转换、大气折射、大气质量、视差角、银道坐标
-- ✅ 七大行星坐标、距日距地距离、特殊天象、物理星历、视直径、相位、视差角与节点
+- ✅ 七大行星坐标、距日距地距离、特殊天象、水星/金星地心凌日、物理星历、视直径、相位、视差角与节点
 - ✅ 公农历转换（公元前104年-公元3000年）
 - ✅ 9100+恒星数据库
 - ✅ 通用小天体轨道传播、H-G 视星等、视双星位置角/角距

basic/event_boundary.go

@@ -0,0 +1,76 @@
+package basic
+
+import "math"
+
+const exactEventTolerance = 2.0 / 86400.0
+
+func sameEventJD(a, b float64) bool {
+	return math.Abs(a-b) <= exactEventTolerance
+}
+
+func sameEventUTQueryTT(eventUT, queryTT float64) bool {
+	return math.Abs(eventUTQueryTTDelta(eventUT, queryTT)) <= exactEventTolerance
+}
+
+func closestEventUTToQueryTT(queryTT, best float64, candidates ...float64) float64 {
+	bestAbs := math.Abs(eventUTQueryTTDelta(best, queryTT))
+	for _, candidate := range candidates {
+		candidateAbs := math.Abs(eventUTQueryTTDelta(candidate, queryTT))
+		if candidateAbs < bestAbs {
+			best = candidate
+			bestAbs = candidateAbs
+		}
+	}
+	return best
+}
+
+type phaseEventSearchFunc func(jde, degree float64, next uint8) float64
+type simpleEventSearchFunc func(jde float64) float64
+
+func inclusiveLastPhaseEvent(jde, degree float64, fn phaseEventSearchFunc) float64 {
+	last := fn(jde, degree, 0)
+	next := fn(jde, degree, 1)
+	if eventUTQueryBeforeOrEqual(next, jde) && eventUTQueryAfterOrEqual(next, jde) {
+		return next
+	}
+	if eventUTQueryBeforeOrEqual(last, jde) {
+		return last
+	}
+	return last
+}
+
+func inclusiveNextPhaseEvent(jde, degree float64, fn phaseEventSearchFunc) float64 {
+	last := fn(jde, degree, 0)
+	if eventUTQueryBeforeOrEqual(last, jde) && eventUTQueryAfterOrEqual(last, jde) {
+		return last
+	}
+	next := fn(jde, degree, 1)
+	if eventUTQueryAfterOrEqual(next, jde) {
+		return next
+	}
+	return next
+}
+
+func inclusiveLastSimpleEvent(jde float64, lastFn, nextFn simpleEventSearchFunc) float64 {
+	last := lastFn(jde)
+	next := nextFn(jde)
+	if eventUTQueryBeforeOrEqual(next, jde) && eventUTQueryAfterOrEqual(next, jde) {
+		return next
+	}
+	if eventUTQueryBeforeOrEqual(last, jde) {
+		return last
+	}
+	return last
+}
+
+func inclusiveNextSimpleEvent(jde float64, lastFn, nextFn simpleEventSearchFunc) float64 {
+	last := lastFn(jde)
+	if eventUTQueryBeforeOrEqual(last, jde) && eventUTQueryAfterOrEqual(last, jde) {
+		return last
+	}
+	next := nextFn(jde)
+	if eventUTQueryAfterOrEqual(next, jde) {
+		return next
+	}
+	return next
+}

basic/event_refine.go

@@ -40,9 +40,7 @@ func eventZeroBracket(leftJD, leftVal, centerJD, centerVal, rightJD, rightVal fl
 	return 0, 0, 0, 0, false
 }
 
-// eventZeroRefine 细化 seed 附近的零点；若找不到可用括号区间，则退回旧的固定步长扫描。
-// eventZeroRefine refines a nearby zero crossing and falls back to the legacy
-// fixed-step scan when no usable bracket is found.
+// eventZeroRefine 细化 seed 附近的零点；无可用括号区间时退回固定步长扫描。
 func eventZeroRefine(seed, halfWindow, step float64, fn func(float64) float64) float64 {
 	leftJD := seed - halfWindow
 	centerJD := seed

basic/inner_event_window.go

@@ -0,0 +1,183 @@
+package basic
+
+import "math"
+
+const innerEventEpsilon = 4.0 / 86400.0
+
+func eventQueryTTAsUT(queryTT float64) float64 {
+	return TD2UT(queryTT, false)
+}
+
+func eventUTQueryTTDelta(eventUT, queryTT float64) float64 {
+	return eventUT - eventQueryTTAsUT(queryTT)
+}
+
+func eventUTQueryBeforeOrEqual(eventUT, queryTT float64) bool {
+	return eventUTQueryTTDelta(eventUT, queryTT) <= innerEventEpsilon
+}
+
+func eventUTQueryAfterOrEqual(eventUT, queryTT float64) bool {
+	return eventUTQueryTTDelta(eventUT, queryTT) >= -innerEventEpsilon
+}
+
+func eventUTNextQueryTT(eventUT float64) float64 {
+	return TD2UT(eventUT, true) + 1.0
+}
+
+func eventUTLastQueryTT(eventUT float64) float64 {
+	return TD2UT(eventUT, true) - 1.0
+}
+
+func innerNextCycleOffset(delta, period float64) float64 {
+	if delta <= 0 {
+		return -delta * period / 360.0
+	}
+	return (360.0 - delta) * period / 360.0
+}
+
+func innerLastCycleOffset(delta, period float64) float64 {
+	if delta >= 0 {
+		return delta * period / 360.0
+	}
+	return (360.0 + delta) * period / 360.0
+}
+
+func clampFloat64(v, min, max float64) float64 {
+	if v < min {
+		return min
+	}
+	if v > max {
+		return max
+	}
+	return v
+}
+
+func scanWindowForMinAbs(start, end, step float64, fn func(float64) float64) float64 {
+	if end < start {
+		start, end = end, start
+	}
+	if step <= 0 || end == start {
+		return start
+	}
+	bestJD := start
+	bestAbs := math.Abs(fn(start))
+	for jd := start + step; jd < end; jd += step {
+		candidateAbs := math.Abs(fn(jd))
+		if candidateAbs < bestAbs {
+			bestAbs = candidateAbs
+			bestJD = jd
+		}
+	}
+	endAbs := math.Abs(fn(end))
+	if endAbs < bestAbs {
+		return end
+	}
+	return bestJD
+}
+
+func scanWindowForMax(start, end, step float64, fn func(float64) float64) float64 {
+	if end < start {
+		start, end = end, start
+	}
+	if step <= 0 || end == start {
+		return start
+	}
+	bestJD := start
+	bestVal := fn(start)
+	for jd := start + step; jd < end; jd += step {
+		candidateVal := fn(jd)
+		if candidateVal > bestVal {
+			bestVal = candidateVal
+			bestJD = jd
+		}
+	}
+	endVal := fn(end)
+	if endVal > bestVal {
+		return end
+	}
+	return bestJD
+}
+
+func boundedEventZeroRefine(seed, start, end, halfWindow, step float64, fn func(float64) float64) float64 {
+	if end < start {
+		start, end = end, start
+	}
+	if end <= start {
+		return start
+	}
+	maxHalfWindow := (end - start) / 2
+	if halfWindow > maxHalfWindow {
+		halfWindow = maxHalfWindow
+	}
+	if halfWindow <= 0 {
+		return clampFloat64(seed, start, end)
+	}
+	seed = clampFloat64(seed, start+halfWindow, end-halfWindow)
+	return eventZeroRefine(seed, halfWindow, step, fn)
+}
+
+func zeroEventInWindow(start, end, coarseStep, halfWindow, refineStep float64, coarseFn, exactFn func(float64) float64) float64 {
+	if end < start {
+		start, end = end, start
+	}
+	if end <= start {
+		return start
+	}
+	rangeDays := end - start
+	if coarseStep <= 0 || coarseStep > rangeDays {
+		coarseStep = rangeDays / 6.0
+	}
+	if coarseStep < 0.5 {
+		coarseStep = 0.5
+	}
+	if refineStep <= 0 {
+		refineStep = 0.5 / 86400.0
+	}
+	if halfWindow <= 0 {
+		halfWindow = coarseStep
+	}
+	guess := scanWindowForMinAbs(start, end, coarseStep, coarseFn)
+	return boundedEventZeroRefine(guess, start, end, halfWindow, refineStep, exactFn)
+}
+
+func maximizeInWindow(start, end, coarseStep float64, coarseFn, exactFn func(float64) float64) float64 {
+	if end < start {
+		start, end = end, start
+	}
+	if end <= start {
+		return start
+	}
+	rangeDays := end - start
+	if coarseStep <= 0 || coarseStep > rangeDays {
+		coarseStep = rangeDays / 6.0
+	}
+	if coarseStep < 0.5 {
+		coarseStep = 0.5
+	}
+	guess := scanWindowForMax(start, end, coarseStep, coarseFn)
+	left := clampFloat64(guess-coarseStep, start, end)
+	right := clampFloat64(guess+coarseStep, start, end)
+	if right-left <= innerEventEpsilon {
+		return guess
+	}
+	for i := 0; i < 20; i++ {
+		third := (right - left) / 3.0
+		leftThird := left + third
+		rightThird := right - third
+		if exactFn(leftThird) <= exactFn(rightThird) {
+			left = leftThird
+			continue
+		}
+		right = rightThird
+	}
+	bestJD := guess
+	bestVal := exactFn(bestJD)
+	for _, jd := range []float64{left, (left + right) / 2.0, right} {
+		candidateVal := exactFn(jd)
+		if candidateVal > bestVal {
+			bestVal = candidateVal
+			bestJD = jd
+		}
+	}
+	return bestJD
+}

basic/inner_planet_event_boundary_test.go

@@ -0,0 +1,45 @@
+package basic
+
+import "testing"
+
+func TestInnerPlanetExactEventBoundaryIncludesCurrent(t *testing.T) {
+	cases := []struct {
+		name   string
+		seed   float64
+		lastFn func(float64) float64
+		nextFn func(float64) float64
+	}{
+		{name: "MercuryConjunction", seed: NextMercuryConjunction(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMercuryConjunction, nextFn: NextMercuryConjunction},
+		{name: "MercuryInferior", seed: NextMercuryInferiorConjunctionInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMercuryInferiorConjunctionInclusive, nextFn: NextMercuryInferiorConjunctionInclusive},
+		{name: "MercurySuperior", seed: NextMercurySuperiorConjunctionInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMercurySuperiorConjunctionInclusive, nextFn: NextMercurySuperiorConjunctionInclusive},
+		{name: "MercuryRetrograde", seed: NextMercuryRetrogradeInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMercuryRetrogradeInclusive, nextFn: NextMercuryRetrogradeInclusive},
+		{name: "MercuryP2R", seed: NextMercuryProgradeToRetrogradeInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMercuryProgradeToRetrogradeInclusive, nextFn: NextMercuryProgradeToRetrogradeInclusive},
+		{name: "MercuryR2P", seed: NextMercuryRetrogradeToProgradeInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMercuryRetrogradeToProgradeInclusive, nextFn: NextMercuryRetrogradeToProgradeInclusive},
+		{name: "MercuryGreatestElongation", seed: NextMercuryGreatestElongationInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMercuryGreatestElongationInclusive, nextFn: NextMercuryGreatestElongationInclusive},
+		{name: "MercuryEastElongation", seed: NextMercuryGreatestElongationEastInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMercuryGreatestElongationEastInclusive, nextFn: NextMercuryGreatestElongationEastInclusive},
+		{name: "MercuryWestElongation", seed: NextMercuryGreatestElongationWestInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMercuryGreatestElongationWestInclusive, nextFn: NextMercuryGreatestElongationWestInclusive},
+		{name: "VenusConjunction", seed: NextVenusConjunction(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastVenusConjunction, nextFn: NextVenusConjunction},
+		{name: "VenusInferior", seed: NextVenusInferiorConjunctionInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastVenusInferiorConjunctionInclusive, nextFn: NextVenusInferiorConjunctionInclusive},
+		{name: "VenusSuperior", seed: NextVenusSuperiorConjunctionInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastVenusSuperiorConjunctionInclusive, nextFn: NextVenusSuperiorConjunctionInclusive},
+		{name: "VenusRetrograde", seed: NextVenusRetrogradeInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastVenusRetrogradeInclusive, nextFn: NextVenusRetrogradeInclusive},
+		{name: "VenusP2R", seed: NextVenusProgradeToRetrogradeInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastVenusProgradeToRetrogradeInclusive, nextFn: NextVenusProgradeToRetrogradeInclusive},
+		{name: "VenusR2P", seed: NextVenusRetrogradeToProgradeInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastVenusRetrogradeToProgradeInclusive, nextFn: NextVenusRetrogradeToProgradeInclusive},
+		{name: "VenusGreatestElongation", seed: NextVenusGreatestElongationInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastVenusGreatestElongationInclusive, nextFn: NextVenusGreatestElongationInclusive},
+		{name: "VenusEastElongation", seed: NextVenusGreatestElongationEastInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastVenusGreatestElongationEastInclusive, nextFn: NextVenusGreatestElongationEastInclusive},
+		{name: "VenusWestElongation", seed: NextVenusGreatestElongationWestInclusive(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastVenusGreatestElongationWestInclusive, nextFn: NextVenusGreatestElongationWestInclusive},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			queryTT := TD2UT(tc.seed, true)
+			last := tc.lastFn(queryTT)
+			next := tc.nextFn(queryTT)
+			if !sameEventJD(last, tc.seed) {
+				t.Fatalf("last exact boundary mismatch: got %.12f want %.12f", last, tc.seed)
+			}
+			if !sameEventJD(next, tc.seed) {
+				t.Fatalf("next exact boundary mismatch: got %.12f want %.12f", next, tc.seed)
+			}
+		})
+	}
+}

basic/inner_planet_truth_test.go

@@ -0,0 +1,165 @@
+package basic
+
+import (
+	"encoding/json"
+	"os"
+	"strings"
+	"testing"
+	"time"
+)
+
+type innerBaselineFile struct {
+	Events []innerBaselineEvent `json:"events"`
+}
+
+type innerBaselineEvent struct {
+	Planet          string `json:"planet"`
+	Kind            string `json:"kind"`
+	NAOJHintJST     string `json:"naoj_hint_jst"`
+	Precision       string `json:"precision"`
+	CandidateJST    string `json:"candidate_jst"`
+	VerifiedJST     string `json:"verified_jst"`
+	CandidateSource string `json:"candidate_source"`
+}
+
+func loadInnerBaseline(t *testing.T) innerBaselineFile {
+	t.Helper()
+
+	paths := [][]string{
+		{
+			"testdata/jpl_inner_event_baseline.json",
+			"basic/testdata/jpl_inner_event_baseline.json",
+		},
+		{
+			"testdata/jpl_inner_event_baseline_21c_sample.json",
+			"basic/testdata/jpl_inner_event_baseline_21c_sample.json",
+		},
+		{
+			"testdata/jpl_inner_event_baseline_20c_sample.json",
+			"basic/testdata/jpl_inner_event_baseline_20c_sample.json",
+		},
+		{
+			"testdata/jpl_inner_event_baseline_22c_sample.json",
+			"basic/testdata/jpl_inner_event_baseline_22c_sample.json",
+		},
+	}
+	var merged innerBaselineFile
+	for index, candidates := range paths {
+		var (
+			data []byte
+			err  error
+		)
+		for _, path := range candidates {
+			data, err = os.ReadFile(path)
+			if err == nil {
+				var baseline innerBaselineFile
+				if err := json.Unmarshal(data, &baseline); err != nil {
+					t.Fatal(err)
+				}
+				merged.Events = append(merged.Events, baseline.Events...)
+				break
+			}
+		}
+		if err != nil && index == 0 {
+			t.Fatal(err)
+		}
+	}
+	if len(merged.Events) == 0 {
+		t.Fatal("empty inner baseline file")
+	}
+	return merged
+}
+
+func parseInnerBaselineTime(t *testing.T, value string) time.Time {
+	t.Helper()
+	loc := time.FixedZone("JST", 9*3600)
+	layouts := []string{
+		"2006-01-02 15:04:05 MST",
+		"2006-01-02 15:04 MST",
+		"2006-01-02 15:04:05",
+		"2006-01-02 15:04",
+	}
+	var err error
+	for _, layout := range layouts {
+		when, parseErr := time.ParseInLocation(layout, value, loc)
+		if parseErr == nil {
+			return when
+		}
+		err = parseErr
+	}
+	t.Fatalf("parse baseline time %q: %v", value, err)
+	return time.Time{}
+}
+
+func innerBaselineTolerance(event innerBaselineEvent) time.Duration {
+	switch event.Kind {
+	case "IC", "SC", "P2R", "R2P":
+		return 2 * time.Minute
+	case "GEE", "GEW":
+		return 90 * time.Minute
+	default:
+		return 2 * time.Minute
+	}
+}
+
+func innerEventFuncs(t *testing.T, event innerBaselineEvent) (func(float64) float64, func(float64) float64) {
+	t.Helper()
+	switch event.Planet + ":" + event.Kind {
+	case "Mercury:IC":
+		return LastMercuryInferiorConjunctionInclusive, NextMercuryInferiorConjunctionInclusive
+	case "Mercury:SC":
+		return LastMercurySuperiorConjunctionInclusive, NextMercurySuperiorConjunctionInclusive
+	case "Mercury:P2R":
+		return LastMercuryProgradeToRetrogradeInclusive, NextMercuryProgradeToRetrogradeInclusive
+	case "Mercury:R2P":
+		return LastMercuryRetrogradeToProgradeInclusive, NextMercuryRetrogradeToProgradeInclusive
+	case "Mercury:GEE":
+		return LastMercuryGreatestElongationEastInclusive, NextMercuryGreatestElongationEastInclusive
+	case "Mercury:GEW":
+		return LastMercuryGreatestElongationWestInclusive, NextMercuryGreatestElongationWestInclusive
+	case "Venus:IC":
+		return LastVenusInferiorConjunctionInclusive, NextVenusInferiorConjunctionInclusive
+	case "Venus:SC":
+		return LastVenusSuperiorConjunctionInclusive, NextVenusSuperiorConjunctionInclusive
+	case "Venus:P2R":
+		return LastVenusProgradeToRetrogradeInclusive, NextVenusProgradeToRetrogradeInclusive
+	case "Venus:R2P":
+		return LastVenusRetrogradeToProgradeInclusive, NextVenusRetrogradeToProgradeInclusive
+	case "Venus:GEE":
+		return LastVenusGreatestElongationEastInclusive, NextVenusGreatestElongationEastInclusive
+	case "Venus:GEW":
+		return LastVenusGreatestElongationWestInclusive, NextVenusGreatestElongationWestInclusive
+	default:
+		t.Fatalf("unsupported event %s:%s", event.Planet, event.Kind)
+		return nil, nil
+	}
+}
+
+func assertInnerBaselineEvent(t *testing.T, event innerBaselineEvent, lastFn, nextFn func(float64) float64) {
+	t.Helper()
+	when := parseInnerBaselineTime(t, event.VerifiedJST)
+	before := when.Add(-24 * time.Hour)
+	after := when.Add(24 * time.Hour)
+	next := JDE2DateByZone(nextFn(toUTJD(before)), when.Location(), false)
+	last := JDE2DateByZone(lastFn(toUTJD(after)), when.Location(), false)
+	tolerance := innerBaselineTolerance(event)
+
+	if diff := next.Sub(when); diff < -tolerance || diff > tolerance {
+		t.Fatalf("%s %s next mismatch: got %s want %s tol=%s hint=%s candidate=%s via=%s", event.Planet, event.Kind, next, when, tolerance, event.NAOJHintJST, event.CandidateJST, event.CandidateSource)
+	}
+	if diff := last.Sub(when); diff < -tolerance || diff > tolerance {
+		t.Fatalf("%s %s last mismatch: got %s want %s tol=%s hint=%s candidate=%s via=%s", event.Planet, event.Kind, last, when, tolerance, event.NAOJHintJST, event.CandidateJST, event.CandidateSource)
+	}
+}
+
+func TestInnerPlanetTruthAgainstJPL(t *testing.T) {
+	baseline := loadInnerBaseline(t)
+	for _, event := range baseline.Events {
+		event := event
+		name := strings.Join([]string{event.Planet, event.Kind, event.VerifiedJST}, "_")
+		t.Run(name, func(t *testing.T) {
+			lastFn, nextFn := innerEventFuncs(t, event)
+			assertInnerBaselineEvent(t, event, lastFn, nextFn)
+		})
+	}
+}

basic/jupiter.go

@@ -87,53 +87,22 @@ func JupiterApparentRaDec(jd float64) (float64, float64) {
 }
 
 func EarthJupiterAway(jd float64) float64 {
-	x, y, z := AJupiterXYZ(jd)
-	to := math.Sqrt(x*x + y*y + z*z)
-	return to
+	return planetEarthAwayExplicitN(4, jd, -1)
 }
 
 func JupiterApparentLo(jd float64) float64 {
-	x, y, z := AJupiterXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AJupiterXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo
+	geo, _ := planetApparentGeocentricPositionN(4, jd, -1)
+	return geo.lo
 }
 
 func JupiterApparentBo(jd float64) float64 {
-	x, y, z := AJupiterXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AJupiterXYZ(jd - to)
-	//lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	//lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	//lo+=GXCLo(lo,bo,jd);
-	//bo+=GXCBo(lo,bo,jd)/3600;
-	//lo+=Nutation2000Bi(jd);
-	return bo
+	geo, _ := planetApparentGeocentricPositionN(4, jd, -1)
+	return geo.bo
 }
 
 func JupiterApparentLoBo(jd float64) (float64, float64) {
-	x, y, z := AJupiterXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AJupiterXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo, bo
+	geo, _ := planetApparentGeocentricPositionN(4, jd, -1)
+	return geo.lo, geo.bo
 }
 
 func JupiterMag(jd float64) float64 {

basic/jupiter_events.go

@@ -40,6 +40,28 @@ func jupiterSunLongitudeDeltaN(jde, degree float64, filter bool, n int) float64
 	return sub
 }
 
+func jupiterRADerivative(jde, delta float64) float64 {
+	sub := JupiterApparentRa(jde+delta) - JupiterApparentRa(jde-delta)
+	if sub > 180 {
+		sub -= 360
+	}
+	if sub < -180 {
+		sub += 360
+	}
+	return sub / (2 * delta)
+}
+
+func jupiterRADerivativeN(jde, delta float64, n int) float64 {
+	sub := JupiterApparentRaN(jde+delta, n) - JupiterApparentRaN(jde-delta, n)
+	if sub > 180 {
+		sub -= 360
+	}
+	if sub < -180 {
+		sub += 360
+	}
+	return sub / (2 * delta)
+}
+
 func jupiterConjunctionFull(jde, degree float64, next uint8) float64 {
 	//0=last 1=next
 	daysPerDegree := JUPITER_S_PERIOD / 360
@@ -94,113 +116,92 @@ func jupiterConjunction(jde, degree float64, next uint8) float64 {
 }
 
 func LastJupiterConjunction(jde float64) float64 {
-	return jupiterConjunction(jde, 0, 0)
+	return inclusiveLastPhaseEvent(jde, 0, jupiterConjunction)
 }
 
 func NextJupiterConjunction(jde float64) float64 {
-	return jupiterConjunction(jde, 0, 1)
+	return inclusiveNextPhaseEvent(jde, 0, jupiterConjunction)
 }
 
 func LastJupiterOpposition(jde float64) float64 {
-	return jupiterConjunction(jde, 180, 0)
+	return inclusiveLastPhaseEvent(jde, 180, jupiterConjunction)
 }
 
 func NextJupiterOpposition(jde float64) float64 {
-	return jupiterConjunction(jde, 180, 1)
+	return inclusiveNextPhaseEvent(jde, 180, jupiterConjunction)
 }
 
 func NextJupiterEasternQuadrature(jde float64) float64 {
-	return jupiterConjunction(jde, 90, 1)
+	return inclusiveNextPhaseEvent(jde, 90, jupiterConjunction)
 }
 
 func LastJupiterEasternQuadrature(jde float64) float64 {
-	return jupiterConjunction(jde, 90, 0)
+	return inclusiveLastPhaseEvent(jde, 90, jupiterConjunction)
 }
 
 func NextJupiterWesternQuadrature(jde float64) float64 {
-	return jupiterConjunction(jde, 270, 1)
+	return inclusiveNextPhaseEvent(jde, 270, jupiterConjunction)
 }
 
 func LastJupiterWesternQuadrature(jde float64) float64 {
-	return jupiterConjunction(jde, 270, 0)
+	return inclusiveLastPhaseEvent(jde, 270, jupiterConjunction)
 }
 
-func jupiterRetrograde(jde float64, searchBeforeOpposition bool) float64 {
-	//0=last 1=next
-	raRate := func(jde float64, delta float64) float64 {
-		sub := JupiterApparentRa(jde+delta) - JupiterApparentRa(jde-delta)
-		if sub > 180 {
-			sub -= 360
-		}
-		if sub < -180 {
-			sub += 360
-		}
-		return sub / (2 * delta)
-	}
-	jde = jupiterConjunctionFull(jde, 180, 1)
+func jupiterRetrogradeAroundOpposition(oppositionJD float64, searchBeforeOpposition bool) float64 {
+	oppositionTT := TD2UT(oppositionJD, true)
+	startTT := oppositionTT
+	endTT := oppositionTT
 	if searchBeforeOpposition {
-		jde -= 60
+		easternQuadratureUT := jupiterConjunction(oppositionTT, 90, 0)
+		startTT = TD2UT(easternQuadratureUT, true)
 	} else {
-		jde += 60
+		westernQuadratureUT := jupiterConjunction(oppositionTT, 270, 1)
+		endTT = TD2UT(westernQuadratureUT, true)
 	}
-	for {
-		currentRate := raRate(jde, 1.0/86400.0)
-		if math.Abs(currentRate) > 0.55 {
-			jde += 2
-			continue
-		}
-		break
-	}
-	estimateJD := jde
-	for {
-		prevJD := estimateJD
-		rateValue := raRate(prevJD, 2.0/86400.0)
-		rateSlope := (raRate(prevJD+15.0/86400.0, 2.0/86400.0) - raRate(prevJD-15.0/86400.0, 2.0/86400.0)) / (30.0 / 86400.0)
-		estimateJD = prevJD - rateValue/rateSlope
-		if math.Abs(estimateJD-prevJD) <= 30.0/86400.0 {
-			break
-		}
-	}
-	bestJD := eventZeroRefine(estimateJD, 15.0/86400.0, 0.5/86400.0, func(jd float64) float64 {
-		return raRate(jd, 0.5/86400.0)
+	bestJD := zeroEventInWindow(startTT, endTT, 2.0, 2.0, 30.0/86400.0, func(jd float64) float64 {
+		return jupiterRADerivativeN(jd, 1.0/86400.0, jupiterEventSearchN)
+	}, func(jd float64) float64 {
+		return jupiterRADerivative(jd, 0.5/86400.0)
 	})
 	return TD2UT(bestJD, false)
 }
 
 func NextJupiterRetrogradeToPrograde(jde float64) float64 {
-	date := jupiterRetrograde(jde, false)
-	if date < jde {
-		oppositionJD := jupiterConjunctionFull(jde, 180, 1)
-		return jupiterRetrograde(oppositionJD+10, false)
-	}
+	lastOppositionJD := jupiterConjunctionFull(jde, 180, 0)
+	date := jupiterRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryAfterOrEqual(date, jde) {
 		return date
+	}
+	nextOppositionJD := jupiterConjunctionFull(jde, 180, 1)
+	return jupiterRetrogradeAroundOpposition(nextOppositionJD, false)
 }
 
 func LastJupiterRetrogradeToPrograde(jde float64) float64 {
-	jde = jupiterConjunctionFull(jde, 180, 0) - 10
-	date := jupiterRetrograde(jde, false)
-	if date > jde {
-		oppositionJD := jupiterConjunctionFull(jde, 180, 0)
-		return jupiterRetrograde(oppositionJD-10, false)
-	}
+	lastOppositionJD := jupiterConjunctionFull(jde, 180, 0)
+	date := jupiterRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryBeforeOrEqual(date, jde) {
 		return date
+	}
+	previousOppositionJD := jupiterConjunctionFull(eventUTLastQueryTT(lastOppositionJD), 180, 0)
+	return jupiterRetrogradeAroundOpposition(previousOppositionJD, false)
 }
 
 func NextJupiterProgradeToRetrograde(jde float64) float64 {
-	date := jupiterRetrograde(jde, true)
-	if date < jde {
-		oppositionJD := jupiterConjunctionFull(jde, 180, 1)
-		return jupiterRetrograde(oppositionJD+10, true)
-	}
+	nextOppositionJD := jupiterConjunctionFull(jde, 180, 1)
+	date := jupiterRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryAfterOrEqual(date, jde) {
 		return date
+	}
+	followingOppositionJD := jupiterConjunctionFull(eventUTNextQueryTT(nextOppositionJD), 180, 1)
+	return jupiterRetrogradeAroundOpposition(followingOppositionJD, true)
 }
 
 func LastJupiterProgradeToRetrograde(jde float64) float64 {
-	jde = jupiterConjunctionFull(jde, 180, 0) - 10
-	date := jupiterRetrograde(jde, true)
-	if date > jde {
-		oppositionJD := jupiterConjunctionFull(jde, 180, 0)
-		return jupiterRetrograde(oppositionJD-10, true)
-	}
+	nextOppositionJD := jupiterConjunctionFull(jde, 180, 1)
+	date := jupiterRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryBeforeOrEqual(date, jde) {
 		return date
+	}
+	lastOppositionJD := jupiterConjunctionFull(jde, 180, 0)
+	return jupiterRetrogradeAroundOpposition(lastOppositionJD, true)
 }

basic/mars.go

@@ -87,72 +87,32 @@ func MarsApparentRaDec(jd float64) (float64, float64) {
 }
 
 func EarthMarsAway(jd float64) float64 {
-	x, y, z := AMarsXYZ(jd)
-	to := math.Sqrt(x*x + y*y + z*z)
-	return to
+	return planetEarthAwayExplicitN(3, jd, -1)
 }
 
 func MarsApparentLo(jd float64) float64 {
-	x, y, z := AMarsXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AMarsXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	//bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180.0 / math.Pi
-	//bo = bo * 180 / math.Pi
-	lo = Limit360(lo) + Nutation2000Bi(jd)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	return lo
+	geo, _ := planetApparentGeocentricPositionN(3, jd, -1)
+	return geo.lo
 }
 
 func MarsApparentBo(jd float64) float64 {
-	x, y, z := AMarsXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AMarsXYZ(jd - to)
-	//lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	//lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	//lo+=GXCLo(lo,bo,jd);
-	//bo+=GXCBo(lo,bo,jd)/3600;
-	//lo+=Nutation2000Bi(jd);
-	return bo
+	geo, _ := planetApparentGeocentricPositionN(3, jd, -1)
+	return geo.bo
 }
 
 func MarsApparentLoBo(jd float64) (float64, float64) {
-	x, y, z := AMarsXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AMarsXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo -= GXCLo(lo, bo, jd) / 3600
-	//bo += GXCBo(lo, bo, jd)
-	lo += Nutation2000Bi(jd)
-	return lo, bo
+	geo, _ := planetApparentGeocentricPositionN(3, jd, -1)
+	return geo.lo, geo.bo
 }
 
 func MarsTrueLoBo(jd float64) (float64, float64) {
-	x, y, z := AMarsXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AMarsXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	return lo, bo
+	geo, _ := planetTrueGeocentricPositionN(3, jd, -1)
+	return geo.lo, geo.bo
 }
 
 func MarsTrueLo(jd float64) float64 {
-	x, y, _ := AMarsXYZ(jd)
-	lo := math.Atan2(y, x)
-	lo = lo * 180 / math.Pi
-	lo = Limit360(lo)
-	return lo
+	geo, _ := planetTrueGeocentricPositionN(3, jd, -1)
+	return geo.lo
 }
 
 func MarsMag(jd float64) float64 {

basic/mars_events.go

@@ -116,40 +116,39 @@ func marsConjunction(jde, degree float64, next uint8) float64 {
 }
 
 func LastMarsConjunction(jde float64) float64 {
-	return marsConjunction(jde, 0, 0)
+	return inclusiveLastPhaseEvent(jde, 0, marsConjunction)
 }
 
 func NextMarsConjunction(jde float64) float64 {
-	return marsConjunction(jde, 0, 1)
+	return inclusiveNextPhaseEvent(jde, 0, marsConjunction)
 }
 
 func LastMarsOpposition(jde float64) float64 {
-	return marsConjunction(jde, 180, 0)
+	return inclusiveLastPhaseEvent(jde, 180, marsConjunction)
 }
 
 func NextMarsOpposition(jde float64) float64 {
-	return marsConjunction(jde, 180, 1)
+	return inclusiveNextPhaseEvent(jde, 180, marsConjunction)
 }
 
 func NextMarsEasternQuadrature(jde float64) float64 {
-	return marsConjunction(jde, 90, 1)
+	return inclusiveNextPhaseEvent(jde, 90, marsConjunction)
 }
 
 func LastMarsEasternQuadrature(jde float64) float64 {
-	return marsConjunction(jde, 90, 0)
+	return inclusiveLastPhaseEvent(jde, 90, marsConjunction)
 }
 
 func NextMarsWesternQuadrature(jde float64) float64 {
-	return marsConjunction(jde, 270, 1)
+	return inclusiveNextPhaseEvent(jde, 270, marsConjunction)
 }
 
 func LastMarsWesternQuadrature(jde float64) float64 {
-	return marsConjunction(jde, 270, 0)
+	return inclusiveLastPhaseEvent(jde, 270, marsConjunction)
 }
 
-func marsRetrograde(jde float64, searchBeforeOpposition bool) float64 {
-	//0=last 1=next
-	jde = marsConjunctionFull(jde, 180, 1)
+func marsRetrogradeAroundOpposition(oppositionJD float64, searchBeforeOpposition bool) float64 {
+	jde := oppositionJD
 	if searchBeforeOpposition {
 		jde -= 60
 	} else {
@@ -179,40 +178,66 @@ func marsRetrograde(jde float64, searchBeforeOpposition bool) float64 {
 	return TD2UT(bestJD, false)
 }
 
+func marsOppositionFromBefore(oppositionJD float64) float64 {
+	return marsConjunctionFull(eventUTLastQueryTT(oppositionJD), 180, 1)
+}
+
+func marsOppositionFromAfter(oppositionJD float64) float64 {
+	return marsConjunctionFull(eventUTNextQueryTT(oppositionJD), 180, 0)
+}
+
 func NextMarsRetrogradeToPrograde(jde float64) float64 {
-	date := marsRetrograde(jde, false)
-	if date < jde {
-		oppositionJD := marsConjunctionFull(jde, 180, 1)
-		return marsRetrograde(oppositionJD+10, false)
+	lastOppositionJD := marsConjunctionFull(jde, 180, 0)
+	date := marsRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) {
+		sameOppositionJD := marsOppositionFromBefore(lastOppositionJD)
+		return closestEventUTToQueryTT(jde, date, marsRetrogradeAroundOpposition(sameOppositionJD, false))
+	}
+	if !eventUTQueryAfterOrEqual(date, jde) {
+		nextOppositionJD := marsConjunctionFull(jde, 180, 1)
+		return marsRetrogradeAroundOpposition(nextOppositionJD, false)
 	}
 	return date
 }
 
 func LastMarsRetrogradeToPrograde(jde float64) float64 {
-	jde = marsConjunctionFull(jde, 180, 0) - 10
-	date := marsRetrograde(jde, false)
-	if date > jde {
-		oppositionJD := marsConjunctionFull(jde, 180, 0)
-		return marsRetrograde(oppositionJD-10, false)
+	lastOppositionJD := marsConjunctionFull(jde, 180, 0)
+	date := marsRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) {
+		sameOppositionJD := marsOppositionFromBefore(lastOppositionJD)
+		return closestEventUTToQueryTT(jde, date, marsRetrogradeAroundOpposition(sameOppositionJD, false))
+	}
+	if !eventUTQueryBeforeOrEqual(date, jde) {
+		previousOppositionJD := marsConjunctionFull(eventUTLastQueryTT(lastOppositionJD), 180, 0)
+		return marsRetrogradeAroundOpposition(previousOppositionJD, false)
 	}
 	return date
 }
 
 func NextMarsProgradeToRetrograde(jde float64) float64 {
-	date := marsRetrograde(jde, true)
-	if date < jde {
-		oppositionJD := marsConjunctionFull(jde, 180, 1)
-		return marsRetrograde(oppositionJD+10, true)
+	nextOppositionJD := marsConjunctionFull(jde, 180, 1)
+	date := marsRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) {
+		sameOppositionJD := marsOppositionFromAfter(nextOppositionJD)
+		return closestEventUTToQueryTT(jde, date, marsRetrogradeAroundOpposition(sameOppositionJD, true))
+	}
+	if !eventUTQueryAfterOrEqual(date, jde) {
+		followingOppositionJD := marsConjunctionFull(eventUTNextQueryTT(nextOppositionJD), 180, 1)
+		return marsRetrogradeAroundOpposition(followingOppositionJD, true)
 	}
 	return date
 }
 
 func LastMarsProgradeToRetrograde(jde float64) float64 {
-	jde = marsConjunctionFull(jde, 180, 0) - 10
-	date := marsRetrograde(jde, true)
-	if date > jde {
-		oppositionJD := marsConjunctionFull(jde, 180, 0)
-		return marsRetrograde(oppositionJD-10, true)
+	nextOppositionJD := marsConjunctionFull(jde, 180, 1)
+	date := marsRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) {
+		sameOppositionJD := marsOppositionFromAfter(nextOppositionJD)
+		return closestEventUTToQueryTT(jde, date, marsRetrogradeAroundOpposition(sameOppositionJD, true))
+	}
+	if !eventUTQueryBeforeOrEqual(date, jde) {
+		lastOppositionJD := marsConjunctionFull(jde, 180, 0)
+		return marsRetrogradeAroundOpposition(lastOppositionJD, true)
 	}
 	return date
 }

basic/mercury.go

@@ -80,52 +80,22 @@ func MercuryApparentRaDec(jd float64) (float64, float64) {
 }
 
 func EarthMercuryAway(jd float64) float64 {
-	x, y, z := AMercuryXYZ(jd)
-	to := math.Sqrt(x*x + y*y + z*z)
-	return to
+	return planetEarthAwayExplicitN(1, jd, -1)
 }
 
 func MercuryApparentLo(jd float64) float64 {
-	x, y, z := AMercuryXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AMercuryXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo
+	geo, _ := planetApparentGeocentricPositionN(1, jd, -1)
+	return geo.lo
 }
 
 func MercuryApparentBo(jd float64) float64 {
-	x, y, z := AMercuryXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AMercuryXYZ(jd - to)
-	//lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	//lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	//lo+=GXCLo(lo,bo,jd);
-	//bo+=GXCBo(lo,bo,jd)/3600;
-	//lo+=Nutation2000Bi(jd);
-	return bo
+	geo, _ := planetApparentGeocentricPositionN(1, jd, -1)
+	return geo.bo
 }
 
 func MercuryApparentLoBo(jd float64) (float64, float64) {
-	x, y, z := AMercuryXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AMercuryXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo) + Nutation2000Bi(jd)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	return lo, bo
+	geo, _ := planetApparentGeocentricPositionN(1, jd, -1)
+	return geo.lo, geo.bo
 }
 
 func MercuryMag(jd float64) float64 {

basic/mercury_events.go

@@ -11,6 +11,7 @@ const (
 	MERCURY_S_PERIOD                    = 1 / ((1 / 87.9691) - (1 / 365.256363004))
 	mercuryConjunctionDerivativeStepDay = 2e-5 * 36525.0
 	mercuryLightTimeDaysPerAU           = 0.0057755183
+	mercuryEventSearchN                 = 16
 )
 
 type mercuryConjunctionLBR struct {
@@ -206,41 +207,49 @@ func mercuryConjunction(jde float64, next uint8) float64 {
 }
 
 func LastMercuryConjunction(jde float64) float64 {
-	return mercuryConjunction(jde, 0)
+	return inclusiveLastSimpleEvent(jde, LastMercuryConjunctionStrict, NextMercuryConjunctionStrict)
 }
 
 func NextMercuryConjunction(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastMercuryConjunctionStrict, NextMercuryConjunctionStrict)
+}
+
+func LastMercuryConjunctionStrict(jde float64) float64 {
+	return mercuryConjunction(jde, 0)
+}
+
+func NextMercuryConjunctionStrict(jde float64) float64 {
 	return mercuryConjunction(jde, 1)
 }
 
 func NextMercuryInferiorConjunction(jde float64) float64 {
-	date := NextMercuryConjunction(jde)
+	date := NextMercuryConjunctionStrict(jde)
 	if EarthMercuryAway(date) > EarthAway(date) {
-		return NextMercuryConjunction(date + 2)
+		return NextMercuryConjunctionStrict(date + 2)
 	}
 	return date
 }
 
 func NextMercurySuperiorConjunction(jde float64) float64 {
-	date := NextMercuryConjunction(jde)
+	date := NextMercuryConjunctionStrict(jde)
 	if EarthMercuryAway(date) < EarthAway(date) {
-		return NextMercuryConjunction(date + 2)
+		return NextMercuryConjunctionStrict(date + 2)
 	}
 	return date
 }
 
 func LastMercuryInferiorConjunction(jde float64) float64 {
-	date := LastMercuryConjunction(jde)
+	date := LastMercuryConjunctionStrict(jde)
 	if EarthMercuryAway(date) > EarthAway(date) {
-		return LastMercuryConjunction(date - 2)
+		return LastMercuryConjunctionStrict(date - 2)
 	}
 	return date
 }
 
 func LastMercurySuperiorConjunction(jde float64) float64 {
-	date := LastMercuryConjunction(jde)
+	date := LastMercuryConjunctionStrict(jde)
 	if EarthMercuryAway(date) < EarthAway(date) {
-		return LastMercuryConjunction(date - 2)
+		return LastMercuryConjunctionStrict(date - 2)
 	}
 	return date
 }
@@ -257,16 +266,6 @@ func mercuryRetrograde(jde float64) float64 {
 		}
 		return sub
 	}
-	raRate := func(jde float64, delta float64) float64 {
-		sub := MercuryApparentRa(jde+delta) - MercuryApparentRa(jde-delta)
-		if sub > 180 {
-			sub -= 360
-		}
-		if sub < -180 {
-			sub += 360
-		}
-		return sub / (2 * delta)
-	}
 	lastConjunction := mercuryConjunctionLegacy(jde, 0)
 	nextConjunction := mercuryConjunctionLegacy(jde, 1)
 	currentRADelta := solarRADelta(jde)
@@ -276,7 +275,7 @@ func mercuryRetrograde(jde float64) float64 {
 		jde = lastConjunction + ((nextConjunction - lastConjunction) / 5.5)
 	}
 	for {
-		currentRate := raRate(jde, 1.0/86400.0)
+		currentRate := mercuryRADerivative(jde, 1.0/86400.0)
 		if math.Abs(currentRate) > 0.55 {
 			jde += 2
 			continue
@@ -286,82 +285,212 @@ func mercuryRetrograde(jde float64) float64 {
 	estimateJD := jde
 	for {
 		prevJD := estimateJD
-		rateValue := raRate(prevJD, 2.0/86400.0)
-		rateSlope := (raRate(prevJD+15.0/86400.0, 2.0/86400.0) - raRate(prevJD-15.0/86400.0, 2.0/86400.0)) / (30.0 / 86400.0)
+		rateValue := mercuryRADerivative(prevJD, 2.0/86400.0)
+		rateSlope := (mercuryRADerivative(prevJD+15.0/86400.0, 2.0/86400.0) - mercuryRADerivative(prevJD-15.0/86400.0, 2.0/86400.0)) / (30.0 / 86400.0)
 		estimateJD = prevJD - rateValue/rateSlope
 		if math.Abs(estimateJD-prevJD) <= 30.0/86400.0 {
 			break
 		}
 	}
 	bestJD := eventZeroRefine(estimateJD, 15.0/86400.0, 0.5/86400.0, func(jd float64) float64 {
-		return raRate(jd, 0.5/86400.0)
+		return mercuryRADerivative(jd, 0.5/86400.0)
 	})
 	//fmt.Println((bestJD - lastConjunction) / (nextConjunction - lastConjunction))
 	return TD2UT(bestJD, false)
 }
 
+func mercuryRADerivative(jde, delta float64) float64 {
+	sub := MercuryApparentRa(jde+delta) - MercuryApparentRa(jde-delta)
+	if sub > 180 {
+		sub -= 360
+	}
+	if sub < -180 {
+		sub += 360
+	}
+	return sub / (2 * delta)
+}
+
+func mercuryStationIsProgradeToRetrograde(eventUT float64) bool {
+	for _, offset := range []float64{0.25, 0.5, 1.0} {
+		before := mercuryRADerivative(eventUT-offset, 0.5/86400.0)
+		after := mercuryRADerivative(eventUT+offset, 0.5/86400.0)
+		if before > 0 && after < 0 {
+			return true
+		}
+		if before < 0 && after > 0 {
+			return false
+		}
+	}
+	before := mercuryRADerivative(eventUT-0.25, 0.5/86400.0)
+	after := mercuryRADerivative(eventUT+0.25, 0.5/86400.0)
+	return before > after
+}
+
+func nextMercuryTypedStation(jde float64, progradeToRetrograde bool) float64 {
+	date := NextMercuryRetrogradeStrict(jde)
+	for mercuryStationIsProgradeToRetrograde(date) != progradeToRetrograde {
+		date = NextMercuryRetrogradeStrict(eventUTNextQueryTT(date))
+	}
+	return date
+}
+
+func lastMercuryTypedStation(jde float64, progradeToRetrograde bool) float64 {
+	date := LastMercuryRetrogradeStrict(jde)
+	for mercuryStationIsProgradeToRetrograde(date) != progradeToRetrograde {
+		date = LastMercuryRetrogradeStrict(eventUTLastQueryTT(date))
+	}
+	return date
+}
+
 func NextMercuryRetrograde(jde float64) float64 {
 	date := mercuryRetrograde(jde)
-	if date < jde {
-		nextConjunction := mercuryConjunctionLegacy(jde, 1)
+	if !eventUTQueryAfterOrEqual(date, jde) {
+		nextConjunction := NextMercuryConjunctionStrict(jde)
 		return mercuryRetrograde(nextConjunction + 2)
 	}
 	return date
 }
 
 func LastMercuryRetrograde(jde float64) float64 {
-	lastConjunction := mercuryConjunctionLegacy(jde, 0)
+	lastConjunction := LastMercuryConjunctionStrict(jde)
 	date := mercuryRetrograde(lastConjunction + 2)
-	if date > jde {
-		previousConjunction := mercuryConjunctionLegacy(lastConjunction-2, 0)
+	if !eventUTQueryBeforeOrEqual(date, jde) {
+		previousConjunction := LastMercuryConjunctionStrict(eventUTLastQueryTT(lastConjunction))
 		return mercuryRetrograde(previousConjunction + 2)
 	}
 	return date
 }
 
+func LastMercuryRetrogradeStrict(jde float64) float64 {
+	return LastMercuryRetrograde(jde)
+}
+
+func NextMercuryRetrogradeStrict(jde float64) float64 {
+	return NextMercuryRetrograde(jde)
+}
+
 func NextMercuryProgradeToRetrograde(jde float64) float64 {
-	date := NextMercuryRetrograde(jde)
-	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
-	if sub > 180 {
-		return NextMercuryRetrograde(date + MERCURY_S_PERIOD/2)
-	}
-	return date
+	return nextMercuryTypedStation(jde, true)
 }
 
 func NextMercuryRetrogradeToPrograde(jde float64) float64 {
-	date := NextMercuryRetrograde(jde)
-	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
-	if sub < 180 {
-		return NextMercuryRetrograde(date + 12)
-	}
-	return date
+	return nextMercuryTypedStation(jde, false)
 }
 
 func LastMercuryProgradeToRetrograde(jde float64) float64 {
-	date := LastMercuryRetrograde(jde)
-	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
-	if sub > 180 {
-		return LastMercuryRetrograde(date - 12)
-	}
-	return date
+	return lastMercuryTypedStation(jde, true)
 }
 
 func LastMercuryRetrogradeToPrograde(jde float64) float64 {
-	date := LastMercuryRetrograde(jde)
-	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
-	if sub < 180 {
-		return LastMercuryRetrograde(date - MERCURY_S_PERIOD/2)
-	}
-	return date
+	return lastMercuryTypedStation(jde, false)
 }
 
 func MercurySunElongation(jde float64) float64 {
 	lo1, bo1 := MercuryApparentLoBo(jde)
-	lo2 := SunApparentLo(jde)
+	lo2 := HSunApparentLo(jde)
 	bo2 := HSunTrueBo(jde)
 	return StarAngularSeparation(lo1, bo1, lo2, bo2)
 }
 
+func mercurySunElongationN(jde float64, n int) float64 {
+	lo1, bo1 := MercuryApparentLoBoN(jde, n)
+	lo2 := HSunApparentLoN(jde, n)
+	bo2 := HSunTrueBoN(jde, n)
+	return StarAngularSeparation(lo1, bo1, lo2, bo2)
+}
+
+func mercuryTrueElongationN(jde float64, n int) float64 {
+	earth := mercuryHelioN(-1, jde, n)
+	planetPos := mercuryHelioN(1, jde, n)
+	geo := mercuryGeocentric(planetPos, earth)
+	return StarAngularSeparation(geo.lo, geo.bo, HSunTrueLoN(jde, n), HSunTrueBoN(jde, n))
+}
+
+func mercuryGreatestElongationInWindow(start, end float64) float64 {
+	best := maximizeInWindow(start, end, 2.0, func(jd float64) float64 {
+		return mercuryTrueElongationN(jd, mercuryEventSearchN)
+	}, func(jd float64) float64 {
+		return mercuryTrueElongationN(jd, -1)
+	})
+	return TD2UT(best, false)
+}
+
+func mercuryEastElongationWindowEndingAt(inferior float64) (float64, float64) {
+	lastSuperior := LastMercurySuperiorConjunction(eventUTLastQueryTT(inferior))
+	return lastSuperior + innerEventEpsilon, inferior - innerEventEpsilon
+}
+
+func mercuryWestElongationWindowEndingAt(superior float64) (float64, float64) {
+	lastInferior := LastMercuryInferiorConjunction(eventUTLastQueryTT(superior))
+	return lastInferior + innerEventEpsilon, superior - innerEventEpsilon
+}
+
+func mercuryEastElongationWindowContaining(jde float64) (float64, float64) {
+	nextInferior := NextMercuryInferiorConjunction(jde)
+	start, end := mercuryEastElongationWindowEndingAt(nextInferior)
+	if eventUTQueryBeforeOrEqual(start, jde) {
+		return start, end
+	}
+	currentInferior := LastMercuryInferiorConjunction(jde)
+	return mercuryEastElongationWindowEndingAt(currentInferior)
+}
+
+func mercuryWestElongationWindowContaining(jde float64) (float64, float64) {
+	nextSuperior := NextMercurySuperiorConjunction(jde)
+	start, end := mercuryWestElongationWindowEndingAt(nextSuperior)
+	if eventUTQueryBeforeOrEqual(start, jde) {
+		return start, end
+	}
+	currentSuperior := LastMercurySuperiorConjunction(jde)
+	return mercuryWestElongationWindowEndingAt(currentSuperior)
+}
+
+func nextMercuryGreatestElongationTyped(jde float64, east bool) float64 {
+	if east {
+		start, windowEnd := mercuryEastElongationWindowContaining(jde)
+		for {
+			date := mercuryGreatestElongationInWindow(start, windowEnd)
+			if eventUTQueryAfterOrEqual(date, jde) {
+				return date
+			}
+			nextInferior := NextMercuryInferiorConjunction(eventUTNextQueryTT(windowEnd))
+			start, windowEnd = mercuryEastElongationWindowEndingAt(nextInferior)
+		}
+	}
+	start, windowEnd := mercuryWestElongationWindowContaining(jde)
+	for {
+		date := mercuryGreatestElongationInWindow(start, windowEnd)
+		if eventUTQueryAfterOrEqual(date, jde) {
+			return date
+		}
+		nextSuperior := NextMercurySuperiorConjunction(eventUTNextQueryTT(windowEnd))
+		start, windowEnd = mercuryWestElongationWindowEndingAt(nextSuperior)
+	}
+}
+
+func lastMercuryGreatestElongationTyped(jde float64, east bool) float64 {
+	if east {
+		start, windowEnd := mercuryEastElongationWindowContaining(jde)
+		for {
+			date := mercuryGreatestElongationInWindow(start, windowEnd)
+			if eventUTQueryBeforeOrEqual(date, jde) {
+				return date
+			}
+			prevInferior := LastMercuryInferiorConjunction(eventUTLastQueryTT(start))
+			start, windowEnd = mercuryEastElongationWindowEndingAt(prevInferior)
+		}
+	}
+	start, windowEnd := mercuryWestElongationWindowContaining(jde)
+	for {
+		date := mercuryGreatestElongationInWindow(start, windowEnd)
+		if eventUTQueryBeforeOrEqual(date, jde) {
+			return date
+		}
+		prevSuperior := LastMercurySuperiorConjunction(eventUTLastQueryTT(start))
+		start, windowEnd = mercuryWestElongationWindowEndingAt(prevSuperior)
+	}
+}
+
 func mercuryGreatestElongation(jde float64) float64 {
 	solarRADelta := func(jde float64) float64 {
 		sub := Limit360(MercuryApparentRa(jde) - SunApparentRa(jde))
@@ -383,8 +512,8 @@ func mercuryGreatestElongation(jde float64) float64 {
 		}
 		return sub / (2 * delta)
 	}
-	lastConjunction := mercuryConjunctionLegacy(jde, 0)
-	nextConjunction := mercuryConjunctionLegacy(jde, 1)
+	lastConjunction := LastMercuryConjunctionStrict(jde)
+	nextConjunction := NextMercuryConjunctionStrict(jde)
 	currentRADelta := solarRADelta(jde)
 	if currentRADelta > 0 {
 		jde = lastConjunction + ((nextConjunction - lastConjunction) / 5.0 * 2.0)
@@ -417,56 +546,105 @@ func mercuryGreatestElongation(jde float64) float64 {
 }
 
 func NextMercuryGreatestElongation(jde float64) float64 {
-	date := mercuryGreatestElongation(jde)
-	if date < jde {
-		nextConjunction := mercuryConjunctionLegacy(jde, 1)
-		return mercuryGreatestElongation(nextConjunction + 2)
+	east := NextMercuryGreatestElongationEast(jde)
+	west := NextMercuryGreatestElongationWest(jde)
+	if sameEventJD(east, west) {
+		return east
 	}
-	return date
+	if east < west {
+		return east
+	}
+	return west
 }
 
 func LastMercuryGreatestElongation(jde float64) float64 {
-	lastConjunction := mercuryConjunctionLegacy(jde, 0)
-	date := mercuryGreatestElongation(lastConjunction + 2)
-	if date > jde {
-		previousConjunction := mercuryConjunctionLegacy(lastConjunction-2, 0)
-		return mercuryGreatestElongation(previousConjunction + 2)
+	east := LastMercuryGreatestElongationEast(jde)
+	west := LastMercuryGreatestElongationWest(jde)
+	if sameEventJD(east, west) {
+		return east
 	}
-	return date
+	if east > west {
+		return east
+	}
+	return west
+}
+
+func LastMercuryInferiorConjunctionInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastMercuryInferiorConjunction, NextMercuryInferiorConjunction)
+}
+
+func NextMercuryInferiorConjunctionInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastMercuryInferiorConjunction, NextMercuryInferiorConjunction)
+}
+
+func LastMercurySuperiorConjunctionInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastMercurySuperiorConjunction, NextMercurySuperiorConjunction)
+}
+
+func NextMercurySuperiorConjunctionInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastMercurySuperiorConjunction, NextMercurySuperiorConjunction)
+}
+
+func LastMercuryRetrogradeInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastMercuryRetrograde, NextMercuryRetrograde)
+}
+
+func NextMercuryRetrogradeInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastMercuryRetrograde, NextMercuryRetrograde)
+}
+
+func LastMercuryProgradeToRetrogradeInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastMercuryProgradeToRetrograde, NextMercuryProgradeToRetrograde)
+}
+
+func NextMercuryProgradeToRetrogradeInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastMercuryProgradeToRetrograde, NextMercuryProgradeToRetrograde)
+}
+
+func LastMercuryRetrogradeToProgradeInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastMercuryRetrogradeToPrograde, NextMercuryRetrogradeToPrograde)
+}
+
+func NextMercuryRetrogradeToProgradeInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastMercuryRetrogradeToPrograde, NextMercuryRetrogradeToPrograde)
+}
+
+func LastMercuryGreatestElongationInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastMercuryGreatestElongation, NextMercuryGreatestElongation)
+}
+
+func NextMercuryGreatestElongationInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastMercuryGreatestElongation, NextMercuryGreatestElongation)
+}
+
+func LastMercuryGreatestElongationEastInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastMercuryGreatestElongationEast, NextMercuryGreatestElongationEast)
+}
+
+func NextMercuryGreatestElongationEastInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastMercuryGreatestElongationEast, NextMercuryGreatestElongationEast)
+}
+
+func LastMercuryGreatestElongationWestInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastMercuryGreatestElongationWest, NextMercuryGreatestElongationWest)
+}
+
+func NextMercuryGreatestElongationWestInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastMercuryGreatestElongationWest, NextMercuryGreatestElongationWest)
 }
 
 func NextMercuryGreatestElongationEast(jde float64) float64 {
-	date := NextMercuryGreatestElongation(jde)
-	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
-	if sub > 180 {
-		return NextMercuryGreatestElongation(date + 1)
-	}
-	return date
+	return nextMercuryGreatestElongationTyped(jde, true)
 }
 
 func NextMercuryGreatestElongationWest(jde float64) float64 {
-	date := NextMercuryGreatestElongation(jde)
-	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
-	if sub < 180 {
-		return NextMercuryGreatestElongation(date + 1)
-	}
-	return date
+	return nextMercuryGreatestElongationTyped(jde, false)
 }
 
 func LastMercuryGreatestElongationEast(jde float64) float64 {
-	date := LastMercuryGreatestElongation(jde)
-	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
-	if sub > 180 {
-		return LastMercuryGreatestElongation(date - 1)
-	}
-	return date
+	return lastMercuryGreatestElongationTyped(jde, true)
 }
 
 func LastMercuryGreatestElongationWest(jde float64) float64 {
-	date := LastMercuryGreatestElongation(jde)
-	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
-	if sub < 180 {
-		return LastMercuryGreatestElongation(date - 1)
-	}
-	return date
+	return lastMercuryGreatestElongationTyped(jde, false)
 }

basic/mercury_station_regression_test.go

@@ -0,0 +1,40 @@
+package basic
+
+import (
+	"math"
+	"testing"
+	"time"
+)
+
+func mercuryTTJDJST(year int, month time.Month, day, hour, minute, second int) float64 {
+	loc := time.FixedZone("JST", 9*3600)
+	return TD2UT(Date2JDE(time.Date(year, month, day, hour, minute, second, 0, loc).UTC()), true)
+}
+
+func TestMercuryTypedStationRegression1929(t *testing.T) {
+	loc := time.FixedZone("JST", 9*3600)
+	const tolerance = 30.0 / 86400.0
+
+	query := mercuryTTJDJST(1929, time.September, 20, 0, 0, 0)
+	wantP2R := mercuryTTJDJST(1929, time.September, 26, 1, 58, 0)
+	wantR2P := mercuryTTJDJST(1929, time.October, 16, 23, 32, 33)
+
+	nextP2R := NextMercuryProgradeToRetrograde(query)
+	nextR2P := NextMercuryRetrogradeToPrograde(query)
+	if math.Abs(nextP2R-wantP2R) > tolerance {
+		t.Fatalf("next P2R mismatch: got %s want %s", JDE2DateByZone(nextP2R, loc, false), JDE2DateByZone(wantP2R, loc, false))
+	}
+	if math.Abs(nextR2P-wantR2P) > tolerance {
+		t.Fatalf("next R2P mismatch: got %s want %s", JDE2DateByZone(nextR2P, loc, false), JDE2DateByZone(wantR2P, loc, false))
+	}
+
+	query = mercuryTTJDJST(1929, time.October, 20, 0, 0, 0)
+	lastP2R := LastMercuryProgradeToRetrograde(query)
+	lastR2P := LastMercuryRetrogradeToPrograde(query)
+	if math.Abs(lastP2R-wantP2R) > tolerance {
+		t.Fatalf("last P2R mismatch: got %s want %s", JDE2DateByZone(lastP2R, loc, false), JDE2DateByZone(wantP2R, loc, false))
+	}
+	if math.Abs(lastR2P-wantR2P) > tolerance {
+		t.Fatalf("last R2P mismatch: got %s want %s", JDE2DateByZone(lastR2P, loc, false), JDE2DateByZone(wantR2P, loc, false))
+	}
+}

basic/neptune.go

@@ -87,53 +87,22 @@ func NeptuneApparentRaDec(jd float64) (float64, float64) {
 }
 
 func EarthNeptuneAway(jd float64) float64 {
-	x, y, z := ANeptuneXYZ(jd)
-	to := math.Sqrt(x*x + y*y + z*z)
-	return to
+	return planetEarthAwayExplicitN(7, jd, -1)
 }
 
 func NeptuneApparentLo(jd float64) float64 {
-	x, y, z := ANeptuneXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = ANeptuneXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo
+	geo, _ := planetApparentGeocentricPositionN(7, jd, -1)
+	return geo.lo
 }
 
 func NeptuneApparentBo(jd float64) float64 {
-	x, y, z := ANeptuneXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = ANeptuneXYZ(jd - to)
-	//lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	//lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	//lo+=GXCLo(lo,bo,jd);
-	//bo+=GXCBo(lo,bo,jd)/3600;
-	//lo+=Nutation2000Bi(jd);
-	return bo
+	geo, _ := planetApparentGeocentricPositionN(7, jd, -1)
+	return geo.bo
 }
 
 func NeptuneApparentLoBo(jd float64) (float64, float64) {
-	x, y, z := ANeptuneXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = ANeptuneXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo, bo
+	geo, _ := planetApparentGeocentricPositionN(7, jd, -1)
+	return geo.lo, geo.bo
 }
 
 func NeptuneMag(jd float64) float64 {

basic/neptune_events.go

@@ -9,7 +9,7 @@ import (
 // Pos
 
 const (
-	NEPTUNE_S_PERIOD            = 1 / ((1 / 365.256363004) - (1 / 4332.59))
+	NEPTUNE_S_PERIOD            = 1 / ((1 / 365.256363004) - (1 / 60190.03))
 	neptuneEventSearchN         = 16
 	neptunePhaseCoarseTolerance = 30.0 / 86400.0
 )
@@ -40,6 +40,28 @@ func neptuneSunLongitudeDeltaN(jde, degree float64, filter bool, n int) float64
 	return sub
 }
 
+func neptuneRADerivative(jde, delta float64) float64 {
+	sub := NeptuneApparentRa(jde+delta) - NeptuneApparentRa(jde-delta)
+	if sub > 180 {
+		sub -= 360
+	}
+	if sub < -180 {
+		sub += 360
+	}
+	return sub / (2 * delta)
+}
+
+func neptuneRADerivativeN(jde, delta float64, n int) float64 {
+	sub := NeptuneApparentRaN(jde+delta, n) - NeptuneApparentRaN(jde-delta, n)
+	if sub > 180 {
+		sub -= 360
+	}
+	if sub < -180 {
+		sub += 360
+	}
+	return sub / (2 * delta)
+}
+
 func neptuneConjunctionFull(jde, degree float64, next uint8) float64 {
 	//0=last 1=next
 	daysPerDegree := NEPTUNE_S_PERIOD / 360
@@ -94,113 +116,92 @@ func neptuneConjunction(jde, degree float64, next uint8) float64 {
 }
 
 func LastNeptuneConjunction(jde float64) float64 {
-	return neptuneConjunction(jde, 0, 0)
+	return inclusiveLastPhaseEvent(jde, 0, neptuneConjunction)
 }
 
 func NextNeptuneConjunction(jde float64) float64 {
-	return neptuneConjunction(jde, 0, 1)
+	return inclusiveNextPhaseEvent(jde, 0, neptuneConjunction)
 }
 
 func LastNeptuneOpposition(jde float64) float64 {
-	return neptuneConjunction(jde, 180, 0)
+	return inclusiveLastPhaseEvent(jde, 180, neptuneConjunction)
 }
 
 func NextNeptuneOpposition(jde float64) float64 {
-	return neptuneConjunction(jde, 180, 1)
+	return inclusiveNextPhaseEvent(jde, 180, neptuneConjunction)
 }
 
 func NextNeptuneEasternQuadrature(jde float64) float64 {
-	return neptuneConjunction(jde, 90, 1)
+	return inclusiveNextPhaseEvent(jde, 90, neptuneConjunction)
 }
 
 func LastNeptuneEasternQuadrature(jde float64) float64 {
-	return neptuneConjunction(jde, 90, 0)
+	return inclusiveLastPhaseEvent(jde, 90, neptuneConjunction)
 }
 
 func NextNeptuneWesternQuadrature(jde float64) float64 {
-	return neptuneConjunction(jde, 270, 1)
+	return inclusiveNextPhaseEvent(jde, 270, neptuneConjunction)
 }
 
 func LastNeptuneWesternQuadrature(jde float64) float64 {
-	return neptuneConjunction(jde, 270, 0)
+	return inclusiveLastPhaseEvent(jde, 270, neptuneConjunction)
 }
 
-func neptuneRetrograde(jde float64, searchBeforeOpposition bool) float64 {
-	//0=last 1=next
-	raRate := func(jde float64, delta float64) float64 {
-		sub := NeptuneApparentRa(jde+delta) - NeptuneApparentRa(jde-delta)
-		if sub > 180 {
-			sub -= 360
-		}
-		if sub < -180 {
-			sub += 360
-		}
-		return sub / (2 * delta)
-	}
-	jde = neptuneConjunctionFull(jde, 180, 1)
+func neptuneRetrogradeAroundOpposition(oppositionJD float64, searchBeforeOpposition bool) float64 {
+	oppositionTT := TD2UT(oppositionJD, true)
+	startTT := oppositionTT
+	endTT := oppositionTT
 	if searchBeforeOpposition {
-		jde -= 60
+		easternQuadratureUT := neptuneConjunction(oppositionTT, 90, 0)
+		startTT = TD2UT(easternQuadratureUT, true)
 	} else {
-		jde += 60
+		westernQuadratureUT := neptuneConjunction(oppositionTT, 270, 1)
+		endTT = TD2UT(westernQuadratureUT, true)
 	}
-	for {
-		currentRate := raRate(jde, 1.0/86400.0)
-		if math.Abs(currentRate) > 0.55 {
-			jde += 2
-			continue
-		}
-		break
-	}
-	estimateJD := jde
-	for {
-		prevJD := estimateJD
-		rateValue := raRate(prevJD, 2.0/86400.0)
-		rateSlope := (raRate(prevJD+15.0/86400.0, 2.0/86400.0) - raRate(prevJD-15.0/86400.0, 2.0/86400.0)) / (30.0 / 86400.0)
-		estimateJD = prevJD - rateValue/rateSlope
-		if math.Abs(estimateJD-prevJD) <= 30.0/86400.0 {
-			break
-		}
-	}
-	bestJD := eventZeroRefine(estimateJD, 15.0/86400.0, 0.5/86400.0, func(jd float64) float64 {
-		return raRate(jd, 0.5/86400.0)
+	bestJD := zeroEventInWindow(startTT, endTT, 2.0, 2.0, 30.0/86400.0, func(jd float64) float64 {
+		return neptuneRADerivativeN(jd, 1.0/86400.0, neptuneEventSearchN)
+	}, func(jd float64) float64 {
+		return neptuneRADerivative(jd, 0.5/86400.0)
 	})
 	return TD2UT(bestJD, false)
 }
 
 func NextNeptuneRetrogradeToPrograde(jde float64) float64 {
-	date := neptuneRetrograde(jde, false)
-	if date < jde {
-		oppositionJD := neptuneConjunctionFull(jde, 180, 1)
-		return neptuneRetrograde(oppositionJD+10, false)
-	}
+	lastOppositionJD := neptuneConjunctionFull(jde, 180, 0)
+	date := neptuneRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryAfterOrEqual(date, jde) {
 		return date
+	}
+	nextOppositionJD := neptuneConjunctionFull(jde, 180, 1)
+	return neptuneRetrogradeAroundOpposition(nextOppositionJD, false)
 }
 
 func LastNeptuneRetrogradeToPrograde(jde float64) float64 {
-	jde = neptuneConjunctionFull(jde, 180, 0) - 10
-	date := neptuneRetrograde(jde, false)
-	if date > jde {
-		oppositionJD := neptuneConjunctionFull(jde, 180, 0)
-		return neptuneRetrograde(oppositionJD-10, false)
-	}
+	lastOppositionJD := neptuneConjunctionFull(jde, 180, 0)
+	date := neptuneRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryBeforeOrEqual(date, jde) {
 		return date
+	}
+	previousOppositionJD := neptuneConjunctionFull(eventUTLastQueryTT(lastOppositionJD), 180, 0)
+	return neptuneRetrogradeAroundOpposition(previousOppositionJD, false)
 }
 
 func NextNeptuneProgradeToRetrograde(jde float64) float64 {
-	date := neptuneRetrograde(jde, true)
-	if date < jde {
-		oppositionJD := neptuneConjunctionFull(jde, 180, 1)
-		return neptuneRetrograde(oppositionJD+10, true)
-	}
+	nextOppositionJD := neptuneConjunctionFull(jde, 180, 1)
+	date := neptuneRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryAfterOrEqual(date, jde) {
 		return date
+	}
+	followingOppositionJD := neptuneConjunctionFull(eventUTNextQueryTT(nextOppositionJD), 180, 1)
+	return neptuneRetrogradeAroundOpposition(followingOppositionJD, true)
 }
 
 func LastNeptuneProgradeToRetrograde(jde float64) float64 {
-	jde = neptuneConjunctionFull(jde, 180, 0) - 10
-	date := neptuneRetrograde(jde, true)
-	if date > jde {
-		oppositionJD := neptuneConjunctionFull(jde, 180, 0)
-		return neptuneRetrograde(oppositionJD-10, true)
-	}
+	nextOppositionJD := neptuneConjunctionFull(jde, 180, 1)
+	date := neptuneRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryBeforeOrEqual(date, jde) {
 		return date
+	}
+	lastOppositionJD := neptuneConjunctionFull(jde, 180, 0)
+	return neptuneRetrogradeAroundOpposition(lastOppositionJD, true)
 }

basic/outer_planet_event_boundary_test.go

@@ -0,0 +1,55 @@
+package basic
+
+import (
+	"testing"
+	"time"
+)
+
+func TestOuterPlanetExactEventBoundaryIncludesCurrent(t *testing.T) {
+	cases := []struct {
+		name   string
+		seed   float64
+		lastFn func(float64) float64
+		nextFn func(float64) float64
+	}{
+		{name: "JupiterConjunction", seed: NextJupiterConjunction(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastJupiterConjunction, nextFn: NextJupiterConjunction},
+		{name: "JupiterOpposition", seed: NextJupiterOpposition(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastJupiterOpposition, nextFn: NextJupiterOpposition},
+		{name: "JupiterEasternQuadrature", seed: NextJupiterEasternQuadrature(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastJupiterEasternQuadrature, nextFn: NextJupiterEasternQuadrature},
+		{name: "JupiterWesternQuadrature", seed: NextJupiterWesternQuadrature(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastJupiterWesternQuadrature, nextFn: NextJupiterWesternQuadrature},
+		{name: "JupiterP2R", seed: NextJupiterProgradeToRetrograde(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastJupiterProgradeToRetrograde, nextFn: NextJupiterProgradeToRetrograde},
+		{name: "JupiterR2P", seed: NextJupiterRetrogradeToPrograde(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastJupiterRetrogradeToPrograde, nextFn: NextJupiterRetrogradeToPrograde},
+		{name: "SaturnOpposition", seed: NextSaturnOpposition(ttjdUTC(2025, 1, 1, 0, 0, 0)), lastFn: LastSaturnOpposition, nextFn: NextSaturnOpposition},
+		{name: "SaturnP2R", seed: NextSaturnProgradeToRetrograde(ttjdUTC(2025, 1, 1, 0, 0, 0)), lastFn: LastSaturnProgradeToRetrograde, nextFn: NextSaturnProgradeToRetrograde},
+		{name: "SaturnR2P", seed: NextSaturnRetrogradeToPrograde(ttjdUTC(2025, 1, 1, 0, 0, 0)), lastFn: LastSaturnRetrogradeToPrograde, nextFn: NextSaturnRetrogradeToPrograde},
+		{name: "UranusOpposition", seed: NextUranusOpposition(ttjdUTC(2025, 1, 1, 0, 0, 0)), lastFn: LastUranusOpposition, nextFn: NextUranusOpposition},
+		{name: "UranusP2R", seed: NextUranusProgradeToRetrograde(ttjdUTC(2025, 1, 1, 0, 0, 0)), lastFn: LastUranusProgradeToRetrograde, nextFn: NextUranusProgradeToRetrograde},
+		{name: "UranusR2P", seed: NextUranusRetrogradeToPrograde(ttjdUTC(2025, 1, 1, 0, 0, 0)), lastFn: LastUranusRetrogradeToPrograde, nextFn: NextUranusRetrogradeToPrograde},
+		{name: "NeptuneOpposition", seed: NextNeptuneOpposition(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastNeptuneOpposition, nextFn: NextNeptuneOpposition},
+		{name: "NeptuneP2R", seed: NextNeptuneProgradeToRetrograde(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastNeptuneProgradeToRetrograde, nextFn: NextNeptuneProgradeToRetrograde},
+		{name: "NeptuneR2P", seed: NextNeptuneRetrogradeToPrograde(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastNeptuneRetrogradeToPrograde, nextFn: NextNeptuneRetrogradeToPrograde},
+		{name: "MarsConjunction", seed: NextMarsConjunction(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMarsConjunction, nextFn: NextMarsConjunction},
+		{name: "MarsOpposition", seed: NextMarsOpposition(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMarsOpposition, nextFn: NextMarsOpposition},
+		{name: "MarsEasternQuadrature", seed: NextMarsEasternQuadrature(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMarsEasternQuadrature, nextFn: NextMarsEasternQuadrature},
+		{name: "MarsWesternQuadrature", seed: NextMarsWesternQuadrature(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMarsWesternQuadrature, nextFn: NextMarsWesternQuadrature},
+		{name: "MarsP2R", seed: NextMarsProgradeToRetrograde(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMarsProgradeToRetrograde, nextFn: NextMarsProgradeToRetrograde},
+		{name: "MarsR2P", seed: NextMarsRetrogradeToPrograde(ttjdUTC(2026, 1, 1, 0, 0, 0)), lastFn: LastMarsRetrogradeToPrograde, nextFn: NextMarsRetrogradeToPrograde},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			queryTT := TD2UT(tc.seed, true)
+			last := tc.lastFn(queryTT)
+			next := tc.nextFn(queryTT)
+			if !sameEventJD(last, tc.seed) {
+				t.Fatalf("last exact boundary mismatch: got %.12f want %.12f", last, tc.seed)
+			}
+			if !sameEventJD(next, tc.seed) {
+				t.Fatalf("next exact boundary mismatch: got %.12f want %.12f", next, tc.seed)
+			}
+		})
+	}
+}
+
+func ttjdUTC(year, month, day, hour, min, sec int) float64 {
+	return TD2UT(Date2JDE(time.Date(year, time.Month(month), day, hour, min, sec, 0, time.UTC)), true)
+}

basic/outer_planet_truth_test.go

@@ -0,0 +1,181 @@
+package basic
+
+import (
+	"encoding/json"
+	"os"
+	"strings"
+	"testing"
+	"time"
+)
+
+type outerTruthBaselineFile struct {
+	Events []outerTruthBaselineEvent `json:"events"`
+}
+
+type outerTruthBaselineEvent struct {
+	Planet          string `json:"planet"`
+	Kind            string `json:"kind"`
+	HintKind        string `json:"hint_kind"`
+	NAOJHintJST     string `json:"naoj_hint_jst"`
+	Precision       string `json:"precision"`
+	CandidateJST    string `json:"candidate_jst"`
+	VerifiedJST     string `json:"verified_jst"`
+	CandidateSource string `json:"candidate_source"`
+}
+
+func loadOuterTruthBaseline(t *testing.T) outerTruthBaselineFile {
+	t.Helper()
+
+	paths := [][]string{
+		{
+			"testdata/jpl_outer_event_baseline.json",
+			"basic/testdata/jpl_outer_event_baseline.json",
+		},
+		{
+			"testdata/jpl_outer_event_baseline_21c_sample.json",
+			"basic/testdata/jpl_outer_event_baseline_21c_sample.json",
+		},
+	}
+
+	var merged outerTruthBaselineFile
+	for index, candidates := range paths {
+		var (
+			data []byte
+			err  error
+		)
+		for _, path := range candidates {
+			data, err = os.ReadFile(path)
+			if err == nil {
+				var baseline outerTruthBaselineFile
+				if err := json.Unmarshal(data, &baseline); err != nil {
+					t.Fatal(err)
+				}
+				merged.Events = append(merged.Events, baseline.Events...)
+				break
+			}
+		}
+		if err != nil && index == 0 {
+			t.Fatal(err)
+		}
+	}
+	if len(merged.Events) == 0 {
+		t.Fatal("empty outer truth baseline file")
+	}
+	return merged
+}
+
+func outerTruthTolerance(event outerTruthBaselineEvent) time.Duration {
+	switch event.Kind {
+	case "CONJ", "OPP", "EQE", "EQW":
+		return 2 * time.Minute
+	default:
+		return 2 * time.Minute
+	}
+}
+
+func outerTruthEventFuncs(t *testing.T, event outerTruthBaselineEvent) (func(float64) float64, func(float64) float64) {
+	t.Helper()
+	switch event.Planet + ":" + event.Kind {
+	case "Jupiter:CONJ":
+		return LastJupiterConjunction, NextJupiterConjunction
+	case "Jupiter:OPP":
+		return LastJupiterOpposition, NextJupiterOpposition
+	case "Jupiter:EQE":
+		return LastJupiterEasternQuadrature, NextJupiterEasternQuadrature
+	case "Jupiter:EQW":
+		return LastJupiterWesternQuadrature, NextJupiterWesternQuadrature
+	case "Jupiter:P2R":
+		return LastJupiterProgradeToRetrograde, NextJupiterProgradeToRetrograde
+	case "Jupiter:R2P":
+		return LastJupiterRetrogradeToPrograde, NextJupiterRetrogradeToPrograde
+	case "Saturn:CONJ":
+		return LastSaturnConjunction, NextSaturnConjunction
+	case "Saturn:OPP":
+		return LastSaturnOpposition, NextSaturnOpposition
+	case "Saturn:EQE":
+		return LastSaturnEasternQuadrature, NextSaturnEasternQuadrature
+	case "Saturn:EQW":
+		return LastSaturnWesternQuadrature, NextSaturnWesternQuadrature
+	case "Saturn:P2R":
+		return LastSaturnProgradeToRetrograde, NextSaturnProgradeToRetrograde
+	case "Saturn:R2P":
+		return LastSaturnRetrogradeToPrograde, NextSaturnRetrogradeToPrograde
+	case "Uranus:CONJ":
+		return LastUranusConjunction, NextUranusConjunction
+	case "Uranus:OPP":
+		return LastUranusOpposition, NextUranusOpposition
+	case "Uranus:EQE":
+		return LastUranusEasternQuadrature, NextUranusEasternQuadrature
+	case "Uranus:EQW":
+		return LastUranusWesternQuadrature, NextUranusWesternQuadrature
+	case "Uranus:P2R":
+		return LastUranusProgradeToRetrograde, NextUranusProgradeToRetrograde
+	case "Uranus:R2P":
+		return LastUranusRetrogradeToPrograde, NextUranusRetrogradeToPrograde
+	case "Neptune:CONJ":
+		return LastNeptuneConjunction, NextNeptuneConjunction
+	case "Neptune:OPP":
+		return LastNeptuneOpposition, NextNeptuneOpposition
+	case "Neptune:EQE":
+		return LastNeptuneEasternQuadrature, NextNeptuneEasternQuadrature
+	case "Neptune:EQW":
+		return LastNeptuneWesternQuadrature, NextNeptuneWesternQuadrature
+	case "Neptune:P2R":
+		return LastNeptuneProgradeToRetrograde, NextNeptuneProgradeToRetrograde
+	case "Neptune:R2P":
+		return LastNeptuneRetrogradeToPrograde, NextNeptuneRetrogradeToPrograde
+	default:
+		t.Fatalf("unsupported outer event %s:%s", event.Planet, event.Kind)
+		return nil, nil
+	}
+}
+
+func assertOuterTruthBaselineEvent(t *testing.T, event outerTruthBaselineEvent, lastFn, nextFn func(float64) float64) {
+	t.Helper()
+	when := parseInnerBaselineTime(t, event.VerifiedJST)
+	before := when.Add(-7 * 24 * time.Hour)
+	after := when.Add(7 * 24 * time.Hour)
+	next := JDE2DateByZone(nextFn(toUTJD(before)), when.Location(), false)
+	last := JDE2DateByZone(lastFn(toUTJD(after)), when.Location(), false)
+	tolerance := outerTruthTolerance(event)
+
+	if diff := next.Sub(when); diff < -tolerance || diff > tolerance {
+		t.Fatalf("%s %s next mismatch: got %s want %s tol=%s hint=%s candidate=%s via=%s", event.Planet, event.Kind, next, when, tolerance, event.NAOJHintJST, event.CandidateJST, event.CandidateSource)
+	}
+	if diff := last.Sub(when); diff < -tolerance || diff > tolerance {
+		t.Fatalf("%s %s last mismatch: got %s want %s tol=%s hint=%s candidate=%s via=%s", event.Planet, event.Kind, last, when, tolerance, event.NAOJHintJST, event.CandidateJST, event.CandidateSource)
+	}
+}
+
+func TestOuterPlanetPhaseTruthAgainstJPL(t *testing.T) {
+	baseline := loadOuterTruthBaseline(t)
+	for _, event := range baseline.Events {
+		event := event
+		switch event.Kind {
+		case "P2R", "R2P":
+			// Station rows are retained as JPL apparent-RA reference data for
+			// future refinement. Current station behavior is constrained by the
+			// library's existing station baseline instead of these reference rows.
+			continue
+		}
+		name := strings.Join([]string{event.Planet, event.Kind, event.VerifiedJST}, "_")
+		t.Run(name, func(t *testing.T) {
+			lastFn, nextFn := outerTruthEventFuncs(t, event)
+			assertOuterTruthBaselineEvent(t, event, lastFn, nextFn)
+		})
+	}
+}
+
+func TestOuterPlanetStationJPLReferenceLoaded(t *testing.T) {
+	baseline := loadOuterTruthBaseline(t)
+	count := 0
+	for _, event := range baseline.Events {
+		switch event.Kind {
+		case "P2R", "R2P":
+			count++
+		}
+	}
+	if count == 0 {
+		t.Fatal("missing outer station JPL reference rows")
+	}
+}

basic/planet_apparent.go

@@ -0,0 +1,84 @@
+package basic
+
+import (
+	"math"
+
+	"b612.me/astro/planet"
+	. "b612.me/astro/tools"
+)
+
+type planetGeocentricPosition struct {
+	x  float64
+	y  float64
+	z  float64
+	lo float64
+	bo float64
+}
+
+func planetHeliocentricXYZN(planetIndex int, jd float64, n int) (float64, float64, float64) {
+	l := planet.WherePlanetN(planetIndex, 0, jd, n)
+	b := planet.WherePlanetN(planetIndex, 1, jd, n)
+	r := planet.WherePlanetN(planetIndex, 2, jd, n)
+	return sphericalToRectangular(l, b, r)
+}
+
+func earthHeliocentricXYZN(jd float64, n int) (float64, float64, float64) {
+	l := planet.WherePlanetN(-1, 0, jd, n)
+	b := planet.WherePlanetN(-1, 1, jd, n)
+	r := planet.WherePlanetN(-1, 2, jd, n)
+	return sphericalToRectangular(l, b, r)
+}
+
+func sphericalToRectangular(lo, bo, radius float64) (float64, float64, float64) {
+	cosBo := math.Cos(bo * math.Pi / 180)
+	return radius * cosBo * math.Cos(lo*math.Pi/180),
+		radius * cosBo * math.Sin(lo*math.Pi/180),
+		radius * math.Sin(bo*math.Pi/180)
+}
+
+func geocentricPositionFromRectangular(x, y, z float64) planetGeocentricPosition {
+	lo := math.Atan2(y, x) * 180 / math.Pi
+	bo := math.Atan2(z, math.Sqrt(x*x+y*y)) * 180 / math.Pi
+	return planetGeocentricPosition{
+		x:  x,
+		y:  y,
+		z:  z,
+		lo: Limit360(lo),
+		bo: bo,
+	}
+}
+
+func planetGeocentricPositionN(planetIndex int, planetJD, earthJD float64, n int) planetGeocentricPosition {
+	px, py, pz := planetHeliocentricXYZN(planetIndex, planetJD, n)
+	ex, ey, ez := earthHeliocentricXYZN(earthJD, n)
+	return geocentricPositionFromRectangular(px-ex, py-ey, pz-ez)
+}
+
+func planetGeocentricPositionWithEarthN(planetIndex int, planetJD float64, ex, ey, ez float64, n int) planetGeocentricPosition {
+	px, py, pz := planetHeliocentricXYZN(planetIndex, planetJD, n)
+	return geocentricPositionFromRectangular(px-ex, py-ey, pz-ez)
+}
+
+func planetApparentGeocentricPositionN(planetIndex int, jd float64, n int) (planetGeocentricPosition, float64) {
+	ex, ey, ez := earthHeliocentricXYZN(jd, n)
+	geoNow := planetGeocentricPositionWithEarthN(planetIndex, jd, ex, ey, ez, n)
+	tau := 0.0057755183 * math.Sqrt(geoNow.x*geoNow.x+geoNow.y*geoNow.y+geoNow.z*geoNow.z)
+	geo := planetGeocentricPositionWithEarthN(planetIndex, jd-tau, ex, ey, ez, n)
+	baseLo := geo.lo
+	baseBo := geo.bo
+	geo.lo = Limit360(baseLo + GXCLo(baseLo, baseBo, jd)/3600.0 + Nutation2000Bi(jd))
+	geo.bo = baseBo + GXCBo(baseLo, baseBo, jd)/3600.0
+	return geo, tau
+}
+
+func planetTrueGeocentricPositionN(planetIndex int, jd float64, n int) (planetGeocentricPosition, float64) {
+	ex, ey, ez := earthHeliocentricXYZN(jd, n)
+	geoNow := planetGeocentricPositionWithEarthN(planetIndex, jd, ex, ey, ez, n)
+	tau := 0.0057755183 * math.Sqrt(geoNow.x*geoNow.x+geoNow.y*geoNow.y+geoNow.z*geoNow.z)
+	return planetGeocentricPositionWithEarthN(planetIndex, jd-tau, ex, ey, ez, n), tau
+}
+
+func planetEarthAwayExplicitN(planetIndex int, jd float64, n int) float64 {
+	geoNow := planetGeocentricPositionN(planetIndex, jd, jd, n)
+	return math.Sqrt(geoNow.x*geoNow.x + geoNow.y*geoNow.y + geoNow.z*geoNow.z)
+}

basic/planet_apparent_external_test.go

@@ -0,0 +1,83 @@
+package basic
+
+import (
+	"encoding/json"
+	"os"
+	"testing"
+	"time"
+)
+
+type planetApparentSample struct {
+	Body              string  `json:"body"`
+	InputUTC          string  `json:"input_utc"`
+	RightAscension    float64 `json:"right_ascension"`
+	Declination       float64 `json:"declination"`
+	EclipticLongitude float64 `json:"ecliptic_longitude"`
+	EclipticLatitude  float64 `json:"ecliptic_latitude"`
+}
+
+func TestPlanetApparentCoordinatesMatchHorizonsBaseline(t *testing.T) {
+	data, err := os.ReadFile("testdata/planet_apparent_baseline.json")
+	if err != nil {
+		t.Fatalf("read baseline: %v", err)
+	}
+
+	var samples []planetApparentSample
+	if err := json.Unmarshal(data, &samples); err != nil {
+		t.Fatalf("decode baseline: %v", err)
+	}
+
+	type apparentCase struct {
+		lo  func(float64) float64
+		bo  func(float64) float64
+		ra  func(float64) float64
+		dec func(float64) float64
+	}
+
+	cases := map[string]apparentCase{
+		"mercury": {lo: MercuryApparentLo, bo: MercuryApparentBo, ra: MercuryApparentRa, dec: MercuryApparentDec},
+		"venus":   {lo: VenusApparentLo, bo: VenusApparentBo, ra: VenusApparentRa, dec: VenusApparentDec},
+		"mars":    {lo: MarsApparentLo, bo: MarsApparentBo, ra: MarsApparentRa, dec: MarsApparentDec},
+		"jupiter": {lo: JupiterApparentLo, bo: JupiterApparentBo, ra: JupiterApparentRa, dec: JupiterApparentDec},
+		"saturn":  {lo: SaturnApparentLo, bo: SaturnApparentBo, ra: SaturnApparentRa, dec: SaturnApparentDec},
+		"uranus":  {lo: UranusApparentLo, bo: UranusApparentBo, ra: UranusApparentRa, dec: UranusApparentDec},
+		"neptune": {lo: NeptuneApparentLo, bo: NeptuneApparentBo, ra: NeptuneApparentRa, dec: NeptuneApparentDec},
+	}
+
+	seen := make(map[string]bool, len(cases))
+	for _, sample := range samples {
+		tc, ok := cases[sample.Body]
+		if !ok {
+			t.Fatalf("unknown body %q", sample.Body)
+		}
+		if seen[sample.Body] {
+			t.Fatalf("duplicate body %q in apparent baseline", sample.Body)
+		}
+		seen[sample.Body] = true
+
+		date, err := time.Parse(time.RFC3339, sample.InputUTC)
+		if err != nil {
+			t.Fatalf("parse sample time %q: %v", sample.InputUTC, err)
+		}
+		jd := TD2UT(Date2JDE(date.UTC()), true)
+		prefix := sample.Body + "." + sample.InputUTC
+
+		assertPlanetApparentAngleClose(t, prefix+".RightAscension", tc.ra(jd), sample.RightAscension, 0.001)
+		assertPlanetPhaseClose(t, prefix+".Declination", tc.dec(jd), sample.Declination, 0.001)
+		assertPlanetApparentAngleClose(t, prefix+".EclipticLongitude", tc.lo(jd), sample.EclipticLongitude, 0.001)
+		assertPlanetPhaseClose(t, prefix+".EclipticLatitude", tc.bo(jd), sample.EclipticLatitude, 0.001)
+	}
+
+	for body := range cases {
+		if !seen[body] {
+			t.Fatalf("missing body %q in apparent baseline", body)
+		}
+	}
+}
+
+func assertPlanetApparentAngleClose(t *testing.T, name string, got, want, tolerance float64) {
+	t.Helper()
+	if diff := angleDiffAbs(got, want); diff > tolerance {
+		t.Fatalf("%s mismatch: got %.12f want %.12f diff %.12f tolerance %.12f", name, got, want, diff, tolerance)
+	}
+}

basic/planet_transit.go

@@ -0,0 +1,520 @@
+package basic
+
+import (
+	"math"
+
+	. "b612.me/astro/tools"
+)
+
+const (
+	planetTransitMeanSolarMotionDegPerDay = 360.0 / 365.2422
+	planetTransitTropicalYearDays         = 365.2422
+	planetTransitSeasonProbeStepDays      = 20.0
+	planetTransitSearchLimit              = 2400
+	planetTransitSearchEpsilonDays        = 1.0 / 86400.0
+	planetTransitGreatestWindowDays       = 1.2
+	planetTransitGreatestToleranceDays    = 0.25 / 86400.0
+	planetTransitContactStepDays          = 0.02
+	planetTransitContactSpanDays          = 1.0
+	planetTransitContactToleranceDays     = 0.25 / 86400.0
+	planetTransitCoarseN                  = 16
+)
+
+// PlanetTransitResult 表示一次地心行星凌日结果。
+//
+// Valid 为 false 时表示没有找到有效凌日。所有时刻字段均为 UT 儒略日。
+// MinimumSeparationArcsec、SunSemidiameterArcsec、PlanetSemidiameterArcsec 的单位均为角秒。
+type PlanetTransitResult struct {
+	Valid bool
+
+	// PlanetIndex 为行星序号，1 表示水星，2 表示金星。
+	PlanetIndex int
+
+	// ExternalIngress / ExternalEgress 为一触 / 四触。
+	ExternalIngress float64
+	ExternalEgress  float64
+	// InternalIngress / InternalEgress 为二触 / 三触。掠凌没有内切接触时为 0。
+	InternalIngress float64
+	InternalEgress  float64
+	// Greatest 为凌甚，即行星中心最接近太阳中心的时刻。
+	Greatest float64
+
+	MinimumSeparationArcsec  float64
+	SunSemidiameterArcsec    float64
+	PlanetSemidiameterArcsec float64
+
+	HasExternal bool
+	HasInternal bool
+}
+
+type planetTransitConfig struct {
+	planetIndex int
+
+	synodicPeriodDays float64
+	anchorInferiorTT  float64
+
+	seasonWindowDays   float64
+	latitudePrefilter  float64
+	conjunctionStepDay float64
+
+	apparentLoN    func(float64, int) float64
+	apparentBoN    func(float64, int) float64
+	apparentRaDecN func(float64, int) (float64, float64)
+	semidiameterN  func(float64, int) float64
+	earthDistanceN func(float64, int) float64
+	nodeN          func(float64, int) float64
+}
+
+type planetTransitState struct {
+	jdTT                  float64
+	separationArcsec      float64
+	separationSquared     float64
+	sunSemidiameter       float64
+	planetSemidiameter    float64
+	externalContactMetric float64
+	internalContactMetric float64
+}
+
+func mercuryTransitConfig() planetTransitConfig {
+	return planetTransitConfig{
+		planetIndex:        1,
+		synodicPeriodDays:  MERCURY_S_PERIOD,
+		anchorInferiorTT:   TD2UT(JDECalc(2019, 11, 11+(15+21.0/60+40.0/3600)/24), true),
+		seasonWindowDays:   12,
+		latitudePrefilter:  1.0,
+		conjunctionStepDay: 0.00001,
+		apparentLoN:        MercuryApparentLoN,
+		apparentBoN:        MercuryApparentBoN,
+		apparentRaDecN:     MercuryApparentRaDecN,
+		semidiameterN:      MercurySemidiameterN,
+		earthDistanceN:     EarthMercuryAwayN,
+		nodeN:              MercuryAscendingNodeN,
+	}
+}
+
+func venusTransitConfig() planetTransitConfig {
+	return planetTransitConfig{
+		planetIndex:        2,
+		synodicPeriodDays:  VENUS_S_PERIOD,
+		anchorInferiorTT:   TD2UT(JDECalc(2012, 6, 6+(1+29.0/60)/24), true),
+		seasonWindowDays:   8,
+		latitudePrefilter:  0.8,
+		conjunctionStepDay: 0.00001,
+		apparentLoN:        VenusApparentLoN,
+		apparentBoN:        VenusApparentBoN,
+		apparentRaDecN:     VenusApparentRaDecN,
+		semidiameterN:      VenusSemidiameterN,
+		earthDistanceN:     EarthVenusAwayN,
+		nodeN:              VenusAscendingNodeN,
+	}
+}
+
+// NextMercuryTransit 返回给定时刻之后的下一次地心水星凌日。
+func NextMercuryTransit(jde float64) PlanetTransitResult {
+	result, _ := searchPlanetTransit(jde, mercuryTransitConfig(), 1, false)
+	return result
+}
+
+// LastMercuryTransit 返回给定时刻之前的上一次地心水星凌日。
+func LastMercuryTransit(jde float64) PlanetTransitResult {
+	result, _ := searchPlanetTransit(jde, mercuryTransitConfig(), -1, true)
+	return result
+}
+
+// ClosestMercuryTransit 返回距给定时刻最近的一次地心水星凌日。
+func ClosestMercuryTransit(jde float64) PlanetTransitResult {
+	return closestPlanetTransit(jde, mercuryTransitConfig())
+}
+
+// NextVenusTransit 返回给定时刻之后的下一次地心金星凌日。
+func NextVenusTransit(jde float64) PlanetTransitResult {
+	result, _ := searchPlanetTransit(jde, venusTransitConfig(), 1, false)
+	return result
+}
+
+// LastVenusTransit 返回给定时刻之前的上一次地心金星凌日。
+func LastVenusTransit(jde float64) PlanetTransitResult {
+	result, _ := searchPlanetTransit(jde, venusTransitConfig(), -1, true)
+	return result
+}
+
+// ClosestVenusTransit 返回距给定时刻最近的一次地心金星凌日。
+func ClosestVenusTransit(jde float64) PlanetTransitResult {
+	return closestPlanetTransit(jde, venusTransitConfig())
+}
+
+func closestPlanetTransit(jde float64, cfg planetTransitConfig) PlanetTransitResult {
+	last, hasLast := searchPlanetTransit(jde, cfg, -1, true)
+	next, hasNext := searchPlanetTransit(jde, cfg, 1, false)
+	switch {
+	case hasLast && !hasNext:
+		return last
+	case !hasLast && hasNext:
+		return next
+	case !hasLast && !hasNext:
+		return PlanetTransitResult{}
+	}
+	if math.Abs(last.Greatest-jde) <= math.Abs(next.Greatest-jde) {
+		return last
+	}
+	return next
+}
+
+func searchPlanetTransit(jde float64, cfg planetTransitConfig, direction int, includeCurrent bool) (PlanetTransitResult, bool) {
+	if !isFiniteFloat(jde) || direction == 0 {
+		return PlanetTransitResult{}, false
+	}
+
+	targetTT := TD2UT(jde, true)
+	probeTT := targetTT
+	for i := 0; i < planetTransitSearchLimit; i++ {
+		seasonTT, ok := nextPlanetTransitSeasonTT(probeTT, cfg, direction)
+		if !ok {
+			return PlanetTransitResult{}, false
+		}
+
+		seedTT := nearestPlanetTransitInferiorSeedTT(seasonTT, cfg)
+		if math.Abs(seedTT-seasonTT) <= cfg.seasonWindowDays {
+			conjunctionTT := refinePlanetTransitInferiorConjunctionTT(seedTT, cfg)
+			if math.Abs(conjunctionTT-seasonTT) <= cfg.seasonWindowDays+1 && isPotentialPlanetTransit(conjunctionTT, cfg) {
+				resultTT, ok := planetTransitAtInferiorConjunctionTT(conjunctionTT, cfg)
+				if ok && planetTransitMatchesDirection(resultTT.Greatest, targetTT, direction, includeCurrent) {
+					return planetTransitResultTTToUT(resultTT), true
+				}
+			}
+		}
+
+		probeTT = seasonTT + float64(direction)*planetTransitSeasonProbeStepDays
+	}
+
+	return PlanetTransitResult{}, false
+}
+
+func nextPlanetTransitSeasonTT(jdTT float64, cfg planetTransitConfig, direction int) (float64, bool) {
+	best := math.NaN()
+	for nodeOffset := 0; nodeOffset <= 1; nodeOffset++ {
+		candidate := estimatePlanetTransitSeasonTT(jdTT, cfg, nodeOffset, direction)
+		candidate = refinePlanetTransitSeasonTT(candidate, cfg, nodeOffset)
+		for !planetTransitMatchesDirection(candidate, jdTT, direction, false) {
+			candidate += float64(direction) * planetTransitTropicalYearDays
+			candidate = refinePlanetTransitSeasonTT(candidate, cfg, nodeOffset)
+		}
+		if !isFiniteFloat(best) || math.Abs(candidate-jdTT) < math.Abs(best-jdTT) {
+			best = candidate
+		}
+	}
+	if !isFiniteFloat(best) {
+		return 0, false
+	}
+	return best, true
+}
+
+func estimatePlanetTransitSeasonTT(jdTT float64, cfg planetTransitConfig, nodeOffset int, direction int) float64 {
+	sunLongitude := HSunApparentLoN(jdTT, planetTransitCoarseN)
+	nodeLongitude := planetTransitNodeLongitude(jdTT, cfg, nodeOffset, planetTransitCoarseN)
+	if direction > 0 {
+		delta := Limit360(nodeLongitude - sunLongitude)
+		if delta <= planetTransitSearchEpsilonDays {
+			delta += 360
+		}
+		return jdTT + delta/planetTransitMeanSolarMotionDegPerDay
+	}
+	delta := Limit360(sunLongitude - nodeLongitude)
+	if delta <= planetTransitSearchEpsilonDays {
+		delta += 360
+	}
+	return jdTT - delta/planetTransitMeanSolarMotionDegPerDay
+}
+
+func refinePlanetTransitSeasonTT(seedTT float64, cfg planetTransitConfig, nodeOffset int) float64 {
+	current := seedTT
+	for i := 0; i < 8; i++ {
+		prev := current
+		value := planetTransitSunNodeLongitudeDelta(prev, cfg, nodeOffset)
+		slope := (planetTransitSunNodeLongitudeDelta(prev+0.5, cfg, nodeOffset) -
+			planetTransitSunNodeLongitudeDelta(prev-0.5, cfg, nodeOffset)) / 1.0
+		if slope == 0 || !isFiniteFloat(slope) {
+			break
+		}
+		current = prev - value/slope
+		if math.Abs(current-prev) <= 0.00001 {
+			break
+		}
+	}
+	return current
+}
+
+func planetTransitSunNodeLongitudeDelta(jdTT float64, cfg planetTransitConfig, nodeOffset int) float64 {
+	return planetTransitAngleDelta(HSunApparentLoN(jdTT, planetTransitCoarseN) -
+		planetTransitNodeLongitude(jdTT, cfg, nodeOffset, planetTransitCoarseN))
+}
+
+func planetTransitNodeLongitude(jdTT float64, cfg planetTransitConfig, nodeOffset int, n int) float64 {
+	return Limit360(cfg.nodeN(jdTT, n) + float64(nodeOffset)*180)
+}
+
+func nearestPlanetTransitInferiorSeedTT(seasonTT float64, cfg planetTransitConfig) float64 {
+	k := math.Round((seasonTT - cfg.anchorInferiorTT) / cfg.synodicPeriodDays)
+	return cfg.anchorInferiorTT + k*cfg.synodicPeriodDays
+}
+
+func refinePlanetTransitInferiorConjunctionTT(seedTT float64, cfg planetTransitConfig) float64 {
+	current := seedTT
+	for i := 0; i < 4; i++ {
+		prev := current
+		value := planetTransitLongitudeDeltaN(prev, cfg, planetTransitCoarseN)
+		slope := (planetTransitLongitudeDeltaN(prev+cfg.conjunctionStepDay, cfg, planetTransitCoarseN) -
+			planetTransitLongitudeDeltaN(prev-cfg.conjunctionStepDay, cfg, planetTransitCoarseN)) / (2 * cfg.conjunctionStepDay)
+		if slope == 0 || !isFiniteFloat(slope) {
+			break
+		}
+		current = prev - value/slope
+		if math.Abs(current-prev) <= 30.0/86400.0 {
+			break
+		}
+	}
+	for i := 0; i < 8; i++ {
+		prev := current
+		value := planetTransitLongitudeDeltaN(prev, cfg, -1)
+		slope := (planetTransitLongitudeDeltaN(prev+cfg.conjunctionStepDay, cfg, -1) -
+			planetTransitLongitudeDeltaN(prev-cfg.conjunctionStepDay, cfg, -1)) / (2 * cfg.conjunctionStepDay)
+		if slope == 0 || !isFiniteFloat(slope) {
+			break
+		}
+		current = prev - value/slope
+		if math.Abs(current-prev) <= cfg.conjunctionStepDay {
+			break
+		}
+	}
+	return current
+}
+
+func planetTransitLongitudeDeltaN(jdTT float64, cfg planetTransitConfig, n int) float64 {
+	return planetTransitAngleDelta(cfg.apparentLoN(jdTT, n) - HSunApparentLoN(jdTT, n))
+}
+
+func isPotentialPlanetTransit(conjunctionTT float64, cfg planetTransitConfig) bool {
+	if cfg.earthDistanceN(conjunctionTT, planetTransitCoarseN) > EarthAwayN(conjunctionTT, planetTransitCoarseN) {
+		return false
+	}
+	return math.Abs(cfg.apparentBoN(conjunctionTT, planetTransitCoarseN)) <= cfg.latitudePrefilter
+}
+
+func planetTransitAtInferiorConjunctionTT(conjunctionTT float64, cfg planetTransitConfig) (PlanetTransitResult, bool) {
+	greatestTT := greatestPlanetTransitTT(conjunctionTT, cfg)
+	greatestState := planetTransitStateAt(greatestTT, cfg, -1)
+	if !isFiniteFloat(greatestState.externalContactMetric) || greatestState.externalContactMetric > 0 {
+		return PlanetTransitResult{}, false
+	}
+
+	result := PlanetTransitResult{
+		Valid:                    true,
+		PlanetIndex:              cfg.planetIndex,
+		Greatest:                 greatestTT,
+		MinimumSeparationArcsec:  greatestState.separationArcsec,
+		SunSemidiameterArcsec:    greatestState.sunSemidiameter,
+		PlanetSemidiameterArcsec: greatestState.planetSemidiameter,
+		HasExternal:              true,
+		HasInternal:              greatestState.internalContactMetric <= 0,
+	}
+
+	externalIngress, ok := refinePlanetTransitContactTT(greatestTT, cfg, -1, false)
+	if !ok {
+		return PlanetTransitResult{}, false
+	}
+	externalEgress, ok := refinePlanetTransitContactTT(greatestTT, cfg, 1, false)
+	if !ok || externalEgress <= externalIngress {
+		return PlanetTransitResult{}, false
+	}
+	result.ExternalIngress = externalIngress
+	result.ExternalEgress = externalEgress
+
+	if result.HasInternal {
+		internalIngress, ok := refinePlanetTransitContactTT(greatestTT, cfg, -1, true)
+		if ok {
+			result.InternalIngress = internalIngress
+		}
+		internalEgress, ok := refinePlanetTransitContactTT(greatestTT, cfg, 1, true)
+		if ok && internalEgress > internalIngress {
+			result.InternalEgress = internalEgress
+		}
+		result.HasInternal = result.InternalIngress != 0 && result.InternalEgress != 0
+	}
+
+	return result, true
+}
+
+func greatestPlanetTransitTT(seedTT float64, cfg planetTransitConfig) float64 {
+	left := seedTT - planetTransitGreatestWindowDays
+	right := seedTT + planetTransitGreatestWindowDays
+	goldenRatio := (math.Sqrt(5) - 1) / 2
+
+	x1 := right - goldenRatio*(right-left)
+	x2 := left + goldenRatio*(right-left)
+	f1 := planetTransitStateAt(x1, cfg, planetTransitCoarseN).separationSquared
+	f2 := planetTransitStateAt(x2, cfg, planetTransitCoarseN).separationSquared
+
+	for i := 0; i < 80 && right-left > planetTransitGreatestToleranceDays; i++ {
+		if f1 <= f2 {
+			right = x2
+			x2 = x1
+			f2 = f1
+			x1 = right - goldenRatio*(right-left)
+			f1 = planetTransitStateAt(x1, cfg, planetTransitCoarseN).separationSquared
+			continue
+		}
+		left = x1
+		x1 = x2
+		f1 = f2
+		x2 = left + goldenRatio*(right-left)
+		f2 = planetTransitStateAt(x2, cfg, planetTransitCoarseN).separationSquared
+	}
+
+	center := (left + right) / 2
+	left = center - 2.0/24.0
+	right = center + 2.0/24.0
+	x1 = right - goldenRatio*(right-left)
+	x2 = left + goldenRatio*(right-left)
+	f1 = planetTransitStateAt(x1, cfg, -1).separationSquared
+	f2 = planetTransitStateAt(x2, cfg, -1).separationSquared
+	for i := 0; i < 80 && right-left > planetTransitGreatestToleranceDays; i++ {
+		if f1 <= f2 {
+			right = x2
+			x2 = x1
+			f2 = f1
+			x1 = right - goldenRatio*(right-left)
+			f1 = planetTransitStateAt(x1, cfg, -1).separationSquared
+			continue
+		}
+		left = x1
+		x1 = x2
+		f1 = f2
+		x2 = left + goldenRatio*(right-left)
+		f2 = planetTransitStateAt(x2, cfg, -1).separationSquared
+	}
+	return (left + right) / 2
+}
+
+func planetTransitStateAt(jdTT float64, cfg planetTransitConfig, n int) planetTransitState {
+	planetRA, planetDec := cfg.apparentRaDecN(jdTT, n)
+	sunRA, sunDec := HSunApparentRaDecN(jdTT, n)
+	separationArcsec := StarAngularSeparation(planetRA, planetDec, sunRA, sunDec) * 3600
+	sunSemidiameter := SunSemidiameterN(jdTT, n)
+	planetSemidiameter := cfg.semidiameterN(jdTT, n)
+	return planetTransitState{
+		jdTT:                  jdTT,
+		separationArcsec:      separationArcsec,
+		separationSquared:     separationArcsec * separationArcsec,
+		sunSemidiameter:       sunSemidiameter,
+		planetSemidiameter:    planetSemidiameter,
+		externalContactMetric: separationArcsec - (sunSemidiameter + planetSemidiameter),
+		internalContactMetric: separationArcsec - (sunSemidiameter - planetSemidiameter),
+	}
+}
+
+func refinePlanetTransitContactTT(greatestTT float64, cfg planetTransitConfig, direction int, internal bool) (float64, bool) {
+	if direction != -1 && direction != 1 {
+		return 0, false
+	}
+	metric := func(jdTT float64) float64 {
+		state := planetTransitStateAt(jdTT, cfg, -1)
+		if internal {
+			return state.internalContactMetric
+		}
+		return state.externalContactMetric
+	}
+
+	nearJD := greatestTT
+	nearValue := metric(nearJD)
+	if !isFiniteFloat(nearValue) || nearValue > 0 {
+		return 0, false
+	}
+	maxSteps := int(math.Ceil(planetTransitContactSpanDays / planetTransitContactStepDays))
+	for i := 1; i <= maxSteps; i++ {
+		farJD := greatestTT + float64(direction)*planetTransitContactStepDays*float64(i)
+		farValue := metric(farJD)
+		if !isFiniteFloat(farValue) {
+			continue
+		}
+		if farValue >= 0 {
+			return bisectPlanetTransitContactTT(nearJD, nearValue, farJD, farValue, metric)
+		}
+		nearJD = farJD
+		nearValue = farValue
+	}
+	return 0, false
+}
+
+func bisectPlanetTransitContactTT(leftJD, leftValue, rightJD, rightValue float64, metric func(float64) float64) (float64, bool) {
+	if leftJD > rightJD {
+		leftJD, rightJD = rightJD, leftJD
+		leftValue, rightValue = rightValue, leftValue
+	}
+	if leftValue == 0 {
+		return leftJD, true
+	}
+	if rightValue == 0 {
+		return rightJD, true
+	}
+	if leftValue*rightValue > 0 {
+		return 0, false
+	}
+
+	for i := 0; i < 80 && rightJD-leftJD > planetTransitContactToleranceDays; i++ {
+		midJD := (leftJD + rightJD) / 2
+		midValue := metric(midJD)
+		if !isFiniteFloat(midValue) {
+			return 0, false
+		}
+		if midValue == 0 {
+			return midJD, true
+		}
+		if leftValue*midValue <= 0 {
+			rightJD = midJD
+			rightValue = midValue
+			continue
+		}
+		leftJD = midJD
+		leftValue = midValue
+	}
+	return (leftJD + rightJD) / 2, true
+}
+
+func planetTransitResultTTToUT(result PlanetTransitResult) PlanetTransitResult {
+	result.Greatest = TD2UT(result.Greatest, false)
+	result.ExternalIngress = TD2UT(result.ExternalIngress, false)
+	result.ExternalEgress = TD2UT(result.ExternalEgress, false)
+	if result.InternalIngress != 0 {
+		result.InternalIngress = TD2UT(result.InternalIngress, false)
+	}
+	if result.InternalEgress != 0 {
+		result.InternalEgress = TD2UT(result.InternalEgress, false)
+	}
+	return result
+}
+
+func planetTransitMatchesDirection(eventJDE, targetJDE float64, direction int, includeCurrent bool) bool {
+	delta := eventJDE - targetJDE
+	if math.Abs(delta) <= planetTransitSearchEpsilonDays {
+		return includeCurrent
+	}
+	if direction > 0 {
+		return delta > 0
+	}
+	return delta < 0
+}
+
+func planetTransitAngleDelta(diff float64) float64 {
+	diff = Limit360(diff)
+	if diff > 180 {
+		diff -= 360
+	}
+	if diff < -180 {
+		diff += 360
+	}
+	return diff
+}
+
+func isFiniteFloat(value float64) bool {
+	return !math.IsNaN(value) && !math.IsInf(value, 0)
+}

basic/planet_transit_test.go

@@ -0,0 +1,145 @@
+package basic
+
+import (
+	"math"
+	"testing"
+	"time"
+)
+
+func TestKnownMercuryTransits(t *testing.T) {
+	tests := []struct {
+		name     string
+		query    time.Time
+		greatest time.Time
+	}{
+		{
+			name:     "2016 May",
+			query:    time.Date(2016, 1, 1, 0, 0, 0, 0, time.UTC),
+			greatest: time.Date(2016, 5, 9, 14, 57, 0, 0, time.UTC),
+		},
+		{
+			name:     "2019 Nov",
+			query:    time.Date(2019, 1, 1, 0, 0, 0, 0, time.UTC),
+			greatest: time.Date(2019, 11, 11, 15, 20, 0, 0, time.UTC),
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			result := NextMercuryTransit(Date2JDE(tc.query))
+			if !result.Valid {
+				t.Fatal("expected valid transit")
+			}
+			got := JDE2DateByZone(result.Greatest, time.UTC, false)
+			t.Logf("start=%s greatest=%s end=%s min=%.3f sun=%.3f planet=%.3f",
+				JDE2DateByZone(result.ExternalIngress, time.UTC, false),
+				got,
+				JDE2DateByZone(result.ExternalEgress, time.UTC, false),
+				result.MinimumSeparationArcsec,
+				result.SunSemidiameterArcsec,
+				result.PlanetSemidiameterArcsec,
+			)
+			if math.Abs(got.Sub(tc.greatest).Seconds()) > 20*60 {
+				t.Fatalf("greatest mismatch: got %s want near %s", got, tc.greatest)
+			}
+			if !result.HasInternal {
+				t.Fatalf("expected internal contacts")
+			}
+			if !(result.ExternalIngress < result.InternalIngress &&
+				result.InternalIngress < result.Greatest &&
+				result.Greatest < result.InternalEgress &&
+				result.InternalEgress < result.ExternalEgress) {
+				t.Fatalf("contacts out of order: %+v", result)
+			}
+		})
+	}
+}
+
+func TestKnownVenusTransits(t *testing.T) {
+	tests := []struct {
+		name     string
+		query    time.Time
+		greatest time.Time
+	}{
+		{
+			name:     "2004 Jun",
+			query:    time.Date(2004, 1, 1, 0, 0, 0, 0, time.UTC),
+			greatest: time.Date(2004, 6, 8, 8, 20, 0, 0, time.UTC),
+		},
+		{
+			name:     "2012 Jun",
+			query:    time.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC),
+			greatest: time.Date(2012, 6, 6, 1, 29, 0, 0, time.UTC),
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			result := NextVenusTransit(Date2JDE(tc.query))
+			if !result.Valid {
+				t.Fatal("expected valid transit")
+			}
+			got := JDE2DateByZone(result.Greatest, time.UTC, false)
+			t.Logf("start=%s greatest=%s end=%s min=%.3f sun=%.3f planet=%.3f",
+				JDE2DateByZone(result.ExternalIngress, time.UTC, false),
+				got,
+				JDE2DateByZone(result.ExternalEgress, time.UTC, false),
+				result.MinimumSeparationArcsec,
+				result.SunSemidiameterArcsec,
+				result.PlanetSemidiameterArcsec,
+			)
+			if math.Abs(got.Sub(tc.greatest).Seconds()) > 20*60 {
+				t.Fatalf("greatest mismatch: got %s want near %s", got, tc.greatest)
+			}
+			if !result.HasInternal {
+				t.Fatalf("expected internal contacts")
+			}
+			if !(result.ExternalIngress < result.InternalIngress &&
+				result.InternalIngress < result.Greatest &&
+				result.Greatest < result.InternalEgress &&
+				result.InternalEgress < result.ExternalEgress) {
+				t.Fatalf("contacts out of order: %+v", result)
+			}
+		})
+	}
+}
+
+func TestTransitSearchSkipsSparseEvents(t *testing.T) {
+	mercuryResult := NextMercuryTransit(Date2JDE(time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)))
+	if !mercuryResult.Valid {
+		t.Fatal("expected Mercury transit")
+	}
+	mercuryGreatest := JDE2DateByZone(mercuryResult.Greatest, time.UTC, false)
+	if mercuryGreatest.Year() != 2032 || mercuryGreatest.Month() != time.November {
+		t.Fatalf("unexpected next Mercury transit: %s", mercuryGreatest)
+	}
+
+	venusResult := NextVenusTransit(Date2JDE(time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)))
+	if !venusResult.Valid {
+		t.Fatal("expected Venus transit")
+	}
+	venusGreatest := JDE2DateByZone(venusResult.Greatest, time.UTC, false)
+	if venusGreatest.Year() != 2117 || venusGreatest.Month() != time.December {
+		t.Fatalf("unexpected next Venus transit: %s", venusGreatest)
+	}
+}
+
+func BenchmarkNextMercuryTransitFrom2026(b *testing.B) {
+	jd := Date2JDE(time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC))
+	for i := 0; i < b.N; i++ {
+		result := NextMercuryTransit(jd)
+		if !result.Valid {
+			b.Fatal("expected valid transit")
+		}
+	}
+}
+
+func BenchmarkNextVenusTransitFrom2026(b *testing.B) {
+	jd := Date2JDE(time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC))
+	for i := 0; i < b.N; i++ {
+		result := NextVenusTransit(jd)
+		if !result.Valid {
+			b.Fatal("expected valid transit")
+		}
+	}
+}

basic/planet_truncated.go

@@ -24,14 +24,8 @@ func planetXYZN(planetIndex int, jd float64, n int) (float64, float64, float64)
 }
 
 func planetApparentLoBoN(planetIndex int, jd float64, n int) (float64, float64) {
-	x, y, z := planetXYZN(planetIndex, jd, n)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = planetXYZN(planetIndex, jd-to, n)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = Limit360(lo*180/math.Pi) + Nutation2000Bi(jd)
-	bo = bo * 180 / math.Pi
-	return lo, bo
+	geo, _ := planetApparentGeocentricPositionN(planetIndex, jd, n)
+	return geo.lo, geo.bo
 }
 
 func planetApparentRaManualN(planetIndex int, jd float64, n int) float64 {
@@ -57,8 +51,7 @@ func planetApparentRaDecManualN(planetIndex int, jd float64, n int) (float64, fl
 }
 
 func planetEarthAwayN(planetIndex int, jd float64, n int) float64 {
-	x, y, z := planetXYZN(planetIndex, jd, n)
-	return math.Sqrt(x*x + y*y + z*z)
+	return planetEarthAwayExplicitN(planetIndex, jd, n)
 }
 
 func planetHeightN(jde, lon, lat, timezone float64, n int, apparentRaDec func(float64, int) (float64, float64)) float64 {

basic/saturn.go

@@ -87,53 +87,22 @@ func SaturnApparentRaDec(jd float64) (float64, float64) {
 }
 
 func EarthSaturnAway(jd float64) float64 {
-	x, y, z := ASaturnXYZ(jd)
-	to := math.Sqrt(x*x + y*y + z*z)
-	return to
+	return planetEarthAwayExplicitN(5, jd, -1)
 }
 
 func SaturnApparentLo(jd float64) float64 {
-	x, y, z := ASaturnXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = ASaturnXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo
+	geo, _ := planetApparentGeocentricPositionN(5, jd, -1)
+	return geo.lo
 }
 
 func SaturnApparentBo(jd float64) float64 {
-	x, y, z := ASaturnXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = ASaturnXYZ(jd - to)
-	//lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	//lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	//lo+=GXCLo(lo,bo,jd);
-	//bo+=GXCBo(lo,bo,jd)/3600;
-	//lo+=Nutation2000Bi(jd);
-	return bo
+	geo, _ := planetApparentGeocentricPositionN(5, jd, -1)
+	return geo.bo
 }
 
 func SaturnApparentLoBo(jd float64) (float64, float64) {
-	x, y, z := ASaturnXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = ASaturnXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo, bo
+	geo, _ := planetApparentGeocentricPositionN(5, jd, -1)
+	return geo.lo, geo.bo
 }
 
 func SaturnMag(jd float64) float64 {

basic/saturn_events.go

@@ -40,6 +40,28 @@ func saturnSunLongitudeDeltaN(jde, degree float64, filter bool, n int) float64 {
 	return sub
 }
 
+func saturnRADerivative(jde, delta float64) float64 {
+	sub := SaturnApparentRa(jde+delta) - SaturnApparentRa(jde-delta)
+	if sub > 180 {
+		sub -= 360
+	}
+	if sub < -180 {
+		sub += 360
+	}
+	return sub / (2 * delta)
+}
+
+func saturnRADerivativeN(jde, delta float64, n int) float64 {
+	sub := SaturnApparentRaN(jde+delta, n) - SaturnApparentRaN(jde-delta, n)
+	if sub > 180 {
+		sub -= 360
+	}
+	if sub < -180 {
+		sub += 360
+	}
+	return sub / (2 * delta)
+}
+
 func saturnConjunctionFull(jde, degree float64, next uint8) float64 {
 	//0=last 1=next
 	daysPerDegree := SATURN_S_PERIOD / 360
@@ -94,113 +116,92 @@ func saturnConjunction(jde, degree float64, next uint8) float64 {
 }
 
 func LastSaturnConjunction(jde float64) float64 {
-	return saturnConjunction(jde, 0, 0)
+	return inclusiveLastPhaseEvent(jde, 0, saturnConjunction)
 }
 
 func NextSaturnConjunction(jde float64) float64 {
-	return saturnConjunction(jde, 0, 1)
+	return inclusiveNextPhaseEvent(jde, 0, saturnConjunction)
 }
 
 func LastSaturnOpposition(jde float64) float64 {
-	return saturnConjunction(jde, 180, 0)
+	return inclusiveLastPhaseEvent(jde, 180, saturnConjunction)
 }
 
 func NextSaturnOpposition(jde float64) float64 {
-	return saturnConjunction(jde, 180, 1)
+	return inclusiveNextPhaseEvent(jde, 180, saturnConjunction)
 }
 
 func NextSaturnEasternQuadrature(jde float64) float64 {
-	return saturnConjunction(jde, 90, 1)
+	return inclusiveNextPhaseEvent(jde, 90, saturnConjunction)
 }
 
 func LastSaturnEasternQuadrature(jde float64) float64 {
-	return saturnConjunction(jde, 90, 0)
+	return inclusiveLastPhaseEvent(jde, 90, saturnConjunction)
 }
 
 func NextSaturnWesternQuadrature(jde float64) float64 {
-	return saturnConjunction(jde, 270, 1)
+	return inclusiveNextPhaseEvent(jde, 270, saturnConjunction)
 }
 
 func LastSaturnWesternQuadrature(jde float64) float64 {
-	return saturnConjunction(jde, 270, 0)
+	return inclusiveLastPhaseEvent(jde, 270, saturnConjunction)
 }
 
-func saturnRetrograde(jde float64, searchBeforeOpposition bool) float64 {
-	//0=last 1=next
-	raRate := func(jde float64, delta float64) float64 {
-		sub := SaturnApparentRa(jde+delta) - SaturnApparentRa(jde-delta)
-		if sub > 180 {
-			sub -= 360
-		}
-		if sub < -180 {
-			sub += 360
-		}
-		return sub / (2 * delta)
-	}
-	jde = saturnConjunctionFull(jde, 180, 1)
+func saturnRetrogradeAroundOpposition(oppositionJD float64, searchBeforeOpposition bool) float64 {
+	oppositionTT := TD2UT(oppositionJD, true)
+	startTT := oppositionTT
+	endTT := oppositionTT
 	if searchBeforeOpposition {
-		jde -= 60
+		easternQuadratureUT := saturnConjunction(oppositionTT, 90, 0)
+		startTT = TD2UT(easternQuadratureUT, true)
 	} else {
-		jde += 60
+		westernQuadratureUT := saturnConjunction(oppositionTT, 270, 1)
+		endTT = TD2UT(westernQuadratureUT, true)
 	}
-	for {
-		currentRate := raRate(jde, 1.0/86400.0)
-		if math.Abs(currentRate) > 0.55 {
-			jde += 2
-			continue
-		}
-		break
-	}
-	estimateJD := jde
-	for {
-		prevJD := estimateJD
-		rateValue := raRate(prevJD, 2.0/86400.0)
-		rateSlope := (raRate(prevJD+15.0/86400.0, 2.0/86400.0) - raRate(prevJD-15.0/86400.0, 2.0/86400.0)) / (30.0 / 86400.0)
-		estimateJD = prevJD - rateValue/rateSlope
-		if math.Abs(estimateJD-prevJD) <= 30.0/86400.0 {
-			break
-		}
-	}
-	bestJD := eventZeroRefine(estimateJD, 15.0/86400.0, 0.5/86400.0, func(jd float64) float64 {
-		return raRate(jd, 0.5/86400.0)
+	bestJD := zeroEventInWindow(startTT, endTT, 2.0, 2.0, 30.0/86400.0, func(jd float64) float64 {
+		return saturnRADerivativeN(jd, 1.0/86400.0, saturnEventSearchN)
+	}, func(jd float64) float64 {
+		return saturnRADerivative(jd, 0.5/86400.0)
 	})
 	return TD2UT(bestJD, false)
 }
 
 func NextSaturnRetrogradeToPrograde(jde float64) float64 {
-	date := saturnRetrograde(jde, false)
-	if date < jde {
-		oppositionJD := saturnConjunctionFull(jde, 180, 1)
-		return saturnRetrograde(oppositionJD+10, false)
-	}
+	lastOppositionJD := saturnConjunctionFull(jde, 180, 0)
+	date := saturnRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryAfterOrEqual(date, jde) {
 		return date
+	}
+	nextOppositionJD := saturnConjunctionFull(jde, 180, 1)
+	return saturnRetrogradeAroundOpposition(nextOppositionJD, false)
 }
 
 func LastSaturnRetrogradeToPrograde(jde float64) float64 {
-	jde = saturnConjunctionFull(jde, 180, 0) - 10
-	date := saturnRetrograde(jde, false)
-	if date > jde {
-		oppositionJD := saturnConjunctionFull(jde, 180, 0)
-		return saturnRetrograde(oppositionJD-10, false)
-	}
+	lastOppositionJD := saturnConjunctionFull(jde, 180, 0)
+	date := saturnRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryBeforeOrEqual(date, jde) {
 		return date
+	}
+	previousOppositionJD := saturnConjunctionFull(eventUTLastQueryTT(lastOppositionJD), 180, 0)
+	return saturnRetrogradeAroundOpposition(previousOppositionJD, false)
 }
 
 func NextSaturnProgradeToRetrograde(jde float64) float64 {
-	date := saturnRetrograde(jde, true)
-	if date < jde {
-		oppositionJD := saturnConjunctionFull(jde, 180, 1)
-		return saturnRetrograde(oppositionJD+10, true)
-	}
+	nextOppositionJD := saturnConjunctionFull(jde, 180, 1)
+	date := saturnRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryAfterOrEqual(date, jde) {
 		return date
+	}
+	followingOppositionJD := saturnConjunctionFull(eventUTNextQueryTT(nextOppositionJD), 180, 1)
+	return saturnRetrogradeAroundOpposition(followingOppositionJD, true)
 }
 
 func LastSaturnProgradeToRetrograde(jde float64) float64 {
-	jde = saturnConjunctionFull(jde, 180, 0) - 10
-	date := saturnRetrograde(jde, true)
-	if date > jde {
-		oppositionJD := saturnConjunctionFull(jde, 180, 0)
-		return saturnRetrograde(oppositionJD-10, true)
-	}
+	nextOppositionJD := saturnConjunctionFull(jde, 180, 1)
+	date := saturnRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryBeforeOrEqual(date, jde) {
 		return date
+	}
+	lastOppositionJD := saturnConjunctionFull(jde, 180, 0)
+	return saturnRetrogradeAroundOpposition(lastOppositionJD, true)
 }

basic/station_truth_test.go

@@ -0,0 +1,207 @@
+package basic
+
+import (
+	"testing"
+	"time"
+)
+
+type stationEvent struct {
+	when time.Time
+	kind string
+}
+
+type stationTruthCase struct {
+	name    string
+	events  []stationEvent
+	lastR2P func(float64) float64
+	nextR2P func(float64) float64
+	lastP2R func(float64) float64
+	nextP2R func(float64) float64
+}
+
+func mustJST(value string) time.Time {
+	loc := time.FixedZone("JST", 9*3600)
+	t, err := time.ParseInLocation("2006-01-02 15:04", value, loc)
+	if err != nil {
+		panic(err)
+	}
+	return t
+}
+
+func toUTJD(t time.Time) float64 {
+	return TD2UT(Date2JDE(t.UTC()), true)
+}
+
+func TestStationTruthAgainstNAOJ(t *testing.T) {
+	cases := []stationTruthCase{
+		{
+			name: "Mars",
+			events: []stationEvent{
+				{when: mustJST("2024-12-08 05:59"), kind: "P2R"},
+				{when: mustJST("2025-01-16 11:39"), kind: "OPP"},
+				{when: mustJST("2025-02-24 18:35"), kind: "R2P"},
+				{when: mustJST("2027-01-12 01:10"), kind: "P2R"},
+				{when: mustJST("2027-02-20 00:51"), kind: "OPP"},
+				{when: mustJST("2027-04-03 02:33"), kind: "R2P"},
+			},
+			lastR2P: LastMarsRetrogradeToPrograde,
+			nextR2P: NextMarsRetrogradeToPrograde,
+			lastP2R: LastMarsProgradeToRetrograde,
+			nextP2R: NextMarsProgradeToRetrograde,
+		},
+		{
+			name: "Jupiter",
+			events: []stationEvent{
+				{when: mustJST("2024-10-09 16:13"), kind: "P2R"},
+				{when: mustJST("2024-12-08 05:58"), kind: "OPP"},
+				{when: mustJST("2025-02-04 22:07"), kind: "R2P"},
+				{when: mustJST("2025-11-12 04:54"), kind: "P2R"},
+				{when: mustJST("2026-01-10 17:42"), kind: "OPP"},
+				{when: mustJST("2026-03-11 11:44"), kind: "R2P"},
+				{when: mustJST("2026-12-13 21:03"), kind: "P2R"},
+				{when: mustJST("2027-02-11 09:29"), kind: "OPP"},
+				{when: mustJST("2027-04-13 15:17"), kind: "R2P"},
+			},
+			lastR2P: LastJupiterRetrogradeToPrograde,
+			nextR2P: NextJupiterRetrogradeToPrograde,
+			lastP2R: LastJupiterProgradeToRetrograde,
+			nextP2R: NextJupiterProgradeToRetrograde,
+		},
+		{
+			name: "Saturn",
+			events: []stationEvent{
+				{when: mustJST("2024-07-01 06:15"), kind: "P2R"},
+				{when: mustJST("2024-09-08 13:35"), kind: "OPP"},
+				{when: mustJST("2024-11-16 14:57"), kind: "R2P"},
+				{when: mustJST("2025-07-14 16:57"), kind: "P2R"},
+				{when: mustJST("2025-09-21 14:46"), kind: "OPP"},
+				{when: mustJST("2025-11-29 09:35"), kind: "R2P"},
+				{when: mustJST("2026-07-28 08:09"), kind: "P2R"},
+				{when: mustJST("2026-10-04 21:29"), kind: "OPP"},
+				{when: mustJST("2026-12-12 08:21"), kind: "R2P"},
+				{when: mustJST("2027-08-11 02:53"), kind: "P2R"},
+				{when: mustJST("2027-10-18 09:36"), kind: "OPP"},
+				{when: mustJST("2027-12-25 12:05"), kind: "R2P"},
+			},
+			lastR2P: LastSaturnRetrogradeToPrograde,
+			nextR2P: NextSaturnRetrogradeToPrograde,
+			lastP2R: LastSaturnProgradeToRetrograde,
+			nextP2R: NextSaturnProgradeToRetrograde,
+		},
+		{
+			name: "Uranus",
+			events: []stationEvent{
+				{when: mustJST("2024-01-27 19:50"), kind: "R2P"},
+				{when: mustJST("2024-09-02 00:44"), kind: "P2R"},
+				{when: mustJST("2024-11-17 11:45"), kind: "OPP"},
+				{when: mustJST("2025-01-31 04:04"), kind: "R2P"},
+				{when: mustJST("2025-09-06 13:55"), kind: "P2R"},
+				{when: mustJST("2025-11-21 21:25"), kind: "OPP"},
+				{when: mustJST("2026-02-04 13:37"), kind: "R2P"},
+				{when: mustJST("2026-09-11 03:19"), kind: "P2R"},
+				{when: mustJST("2026-11-26 07:41"), kind: "OPP"},
+				{when: mustJST("2027-02-08 23:03"), kind: "R2P"},
+				{when: mustJST("2027-09-15 17:50"), kind: "P2R"},
+				{when: mustJST("2027-11-30 18:22"), kind: "OPP"},
+			},
+			lastR2P: LastUranusRetrogradeToPrograde,
+			nextR2P: NextUranusRetrogradeToPrograde,
+			lastP2R: LastUranusProgradeToRetrograde,
+			nextP2R: NextUranusProgradeToRetrograde,
+		},
+		{
+			name: "Neptune",
+			events: []stationEvent{
+				{when: mustJST("2024-07-03 12:08"), kind: "P2R"},
+				{when: mustJST("2024-09-21 09:17"), kind: "OPP"},
+				{when: mustJST("2024-12-08 20:05"), kind: "R2P"},
+				{when: mustJST("2025-07-05 23:30"), kind: "P2R"},
+				{when: mustJST("2025-09-23 21:54"), kind: "OPP"},
+				{when: mustJST("2025-12-11 09:21"), kind: "R2P"},
+				{when: mustJST("2026-07-08 13:02"), kind: "P2R"},
+				{when: mustJST("2026-09-26 10:36"), kind: "OPP"},
+				{when: mustJST("2026-12-13 19:47"), kind: "R2P"},
+				{when: mustJST("2027-07-11 01:06"), kind: "P2R"},
+				{when: mustJST("2027-09-28 23:19"), kind: "OPP"},
+				{when: mustJST("2027-12-16 07:16"), kind: "R2P"},
+			},
+			lastR2P: LastNeptuneRetrogradeToPrograde,
+			nextR2P: NextNeptuneRetrogradeToPrograde,
+			lastP2R: LastNeptuneProgradeToRetrograde,
+			nextP2R: NextNeptuneProgradeToRetrograde,
+		},
+	}
+
+	for _, tc := range cases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			for i, event := range tc.events {
+				switch event.kind {
+				case "P2R":
+					before := event.when.Add(-24 * time.Hour)
+					after := event.when.Add(24 * time.Hour)
+					nextP2R := JDE2DateByZone(tc.nextP2R(toUTJD(before)), event.when.Location(), false)
+					lastP2R := JDE2DateByZone(tc.lastP2R(toUTJD(after)), event.when.Location(), false)
+					if !sameMinute(nextP2R, event.when) {
+						t.Fatalf("%s next P2R mismatch: got %s want %s", tc.name, nextP2R, event.when)
+					}
+					if !sameMinute(lastP2R, event.when) {
+						t.Fatalf("%s last P2R mismatch: got %s want %s", tc.name, lastP2R, event.when)
+					}
+				case "R2P":
+					before := event.when.Add(-24 * time.Hour)
+					after := event.when.Add(24 * time.Hour)
+					nextR2P := JDE2DateByZone(tc.nextR2P(toUTJD(before)), event.when.Location(), false)
+					lastR2P := JDE2DateByZone(tc.lastR2P(toUTJD(after)), event.when.Location(), false)
+					if !sameMinute(nextR2P, event.when) {
+						t.Fatalf("%s next R2P mismatch: got %s want %s", tc.name, nextR2P, event.when)
+					}
+					if !sameMinute(lastR2P, event.when) {
+						t.Fatalf("%s last R2P mismatch: got %s want %s", tc.name, lastR2P, event.when)
+					}
+				case "OPP":
+					prev := nearestOfKindBefore(tc.events, i, "P2R")
+					next := nearestOfKindAfter(tc.events, i, "R2P")
+					if prev.IsZero() || next.IsZero() {
+						continue
+					}
+					query := event.when
+					lastP2R := JDE2DateByZone(tc.lastP2R(toUTJD(query)), query.Location(), false)
+					nextR2P := JDE2DateByZone(tc.nextR2P(toUTJD(query)), query.Location(), false)
+					if !sameMinute(lastP2R, prev) {
+						t.Fatalf("%s opposition last P2R mismatch: got %s want %s", tc.name, lastP2R, prev)
+					}
+					if !sameMinute(nextR2P, next) {
+						t.Fatalf("%s opposition next R2P mismatch: got %s want %s", tc.name, nextR2P, next)
+					}
+				}
+			}
+		})
+	}
+}
+
+func nearestOfKindBefore(events []stationEvent, idx int, kind string) time.Time {
+	for i := idx - 1; i >= 0; i-- {
+		if events[i].kind == kind {
+			return events[i].when
+		}
+	}
+	return time.Time{}
+}
+
+func nearestOfKindAfter(events []stationEvent, idx int, kind string) time.Time {
+	for i := idx + 1; i < len(events); i++ {
+		if events[i].kind == kind {
+			return events[i].when
+		}
+	}
+	return time.Time{}
+}
+
+func sameMinute(got, want time.Time) bool {
+	diff := got.Sub(want)
+	if diff < 0 {
+		diff = -diff
+	}
+	return diff <= 2*time.Minute
+}

basic/testdata/planet_apparent_baseline.json

@@ -0,0 +1,58 @@
+[
+  {
+    "body": "mercury",
+    "input_utc": "2026-01-01T00:00:00Z",
+    "right_ascension": 268.524035973,
+    "declination": -24.001291126,
+    "ecliptic_longitude": 268.6516112,
+    "ecliptic_latitude": -0.5700521
+  },
+  {
+    "body": "venus",
+    "input_utc": "2026-01-01T00:00:00Z",
+    "right_ascension": 280.056455581,
+    "declination": -23.622404581,
+    "ecliptic_longitude": 279.2064734,
+    "ecliptic_latitude": -0.5050645
+  },
+  {
+    "body": "mars",
+    "input_utc": "2026-01-01T00:00:00Z",
+    "right_ascension": 283.879610807,
+    "declination": -23.720007274,
+    "ecliptic_longitude": 282.6881475,
+    "ecliptic_latitude": -0.8911035
+  },
+  {
+    "body": "jupiter",
+    "input_utc": "2026-01-01T00:00:00Z",
+    "right_ascension": 113.124332352,
+    "declination": 21.979135798,
+    "ecliptic_longitude": 111.3575894,
+    "ecliptic_latitude": 0.2391257
+  },
+  {
+    "body": "saturn",
+    "input_utc": "2026-01-01T00:00:00Z",
+    "right_ascension": 357.380959207,
+    "declination": -3.596394732,
+    "ecliptic_longitude": 356.1672313,
+    "ecliptic_latitude": -2.2587419
+  },
+  {
+    "body": "uranus",
+    "input_utc": "2026-01-01T00:00:00Z",
+    "right_ascension": 55.737099009,
+    "declination": 19.509648526,
+    "ecliptic_longitude": 57.9492508,
+    "ecliptic_latitude": -0.1975992
+  },
+  {
+    "body": "neptune",
+    "input_utc": "2026-01-01T00:00:00Z",
+    "right_ascension": 0.077612938,
+    "declination": -1.418610222,
+    "ecliptic_longitude": 359.5068407,
+    "ecliptic_latitude": -1.3324096
+  }
+]

basic/uranus.go

@@ -87,53 +87,22 @@ func UranusApparentRaDec(jd float64) (float64, float64) {
 }
 
 func EarthUranusAway(jd float64) float64 {
-	x, y, z := AUranusXYZ(jd)
-	to := math.Sqrt(x*x + y*y + z*z)
-	return to
+	return planetEarthAwayExplicitN(6, jd, -1)
 }
 
 func UranusApparentLo(jd float64) float64 {
-	x, y, z := AUranusXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AUranusXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo
+	geo, _ := planetApparentGeocentricPositionN(6, jd, -1)
+	return geo.lo
 }
 
 func UranusApparentBo(jd float64) float64 {
-	x, y, z := AUranusXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AUranusXYZ(jd - to)
-	//lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	//lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	//lo+=GXCLo(lo,bo,jd);
-	//bo+=GXCBo(lo,bo,jd)/3600;
-	//lo+=Nutation2000Bi(jd);
-	return bo
+	geo, _ := planetApparentGeocentricPositionN(6, jd, -1)
+	return geo.bo
 }
 
 func UranusApparentLoBo(jd float64) (float64, float64) {
-	x, y, z := AUranusXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AUranusXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo, bo
+	geo, _ := planetApparentGeocentricPositionN(6, jd, -1)
+	return geo.lo, geo.bo
 }
 
 func UranusMag(jd float64) float64 {

basic/uranus_events.go

@@ -40,6 +40,28 @@ func uranusSunLongitudeDeltaN(jde, degree float64, filter bool, n int) float64 {
 	return sub
 }
 
+func uranusRADerivative(jde, delta float64) float64 {
+	sub := UranusApparentRa(jde+delta) - UranusApparentRa(jde-delta)
+	if sub > 180 {
+		sub -= 360
+	}
+	if sub < -180 {
+		sub += 360
+	}
+	return sub / (2 * delta)
+}
+
+func uranusRADerivativeN(jde, delta float64, n int) float64 {
+	sub := UranusApparentRaN(jde+delta, n) - UranusApparentRaN(jde-delta, n)
+	if sub > 180 {
+		sub -= 360
+	}
+	if sub < -180 {
+		sub += 360
+	}
+	return sub / (2 * delta)
+}
+
 func uranusConjunctionFull(jde, degree float64, next uint8) float64 {
 	//0=last 1=next
 	daysPerDegree := URANUS_S_PERIOD / 360
@@ -94,113 +116,92 @@ func uranusConjunction(jde, degree float64, next uint8) float64 {
 }
 
 func LastUranusConjunction(jde float64) float64 {
-	return uranusConjunction(jde, 0, 0)
+	return inclusiveLastPhaseEvent(jde, 0, uranusConjunction)
 }
 
 func NextUranusConjunction(jde float64) float64 {
-	return uranusConjunction(jde, 0, 1)
+	return inclusiveNextPhaseEvent(jde, 0, uranusConjunction)
 }
 
 func LastUranusOpposition(jde float64) float64 {
-	return uranusConjunction(jde, 180, 0)
+	return inclusiveLastPhaseEvent(jde, 180, uranusConjunction)
 }
 
 func NextUranusOpposition(jde float64) float64 {
-	return uranusConjunction(jde, 180, 1)
+	return inclusiveNextPhaseEvent(jde, 180, uranusConjunction)
 }
 
 func NextUranusEasternQuadrature(jde float64) float64 {
-	return uranusConjunction(jde, 90, 1)
+	return inclusiveNextPhaseEvent(jde, 90, uranusConjunction)
 }
 
 func LastUranusEasternQuadrature(jde float64) float64 {
-	return uranusConjunction(jde, 90, 0)
+	return inclusiveLastPhaseEvent(jde, 90, uranusConjunction)
 }
 
 func NextUranusWesternQuadrature(jde float64) float64 {
-	return uranusConjunction(jde, 270, 1)
+	return inclusiveNextPhaseEvent(jde, 270, uranusConjunction)
 }
 
 func LastUranusWesternQuadrature(jde float64) float64 {
-	return uranusConjunction(jde, 270, 0)
+	return inclusiveLastPhaseEvent(jde, 270, uranusConjunction)
 }
 
-func uranusRetrograde(jde float64, searchBeforeOpposition bool) float64 {
-	//0=last 1=next
-	raRate := func(jde float64, delta float64) float64 {
-		sub := UranusApparentRa(jde+delta) - UranusApparentRa(jde-delta)
-		if sub > 180 {
-			sub -= 360
-		}
-		if sub < -180 {
-			sub += 360
-		}
-		return sub / (2 * delta)
-	}
-	jde = uranusConjunctionFull(jde, 180, 1)
+func uranusRetrogradeAroundOpposition(oppositionJD float64, searchBeforeOpposition bool) float64 {
+	oppositionTT := TD2UT(oppositionJD, true)
+	startTT := oppositionTT
+	endTT := oppositionTT
 	if searchBeforeOpposition {
-		jde -= 60
+		easternQuadratureUT := uranusConjunction(oppositionTT, 90, 0)
+		startTT = TD2UT(easternQuadratureUT, true)
 	} else {
-		jde += 60
+		westernQuadratureUT := uranusConjunction(oppositionTT, 270, 1)
+		endTT = TD2UT(westernQuadratureUT, true)
 	}
-	for {
-		currentRate := raRate(jde, 1.0/86400.0)
-		if math.Abs(currentRate) > 0.55 {
-			jde += 2
-			continue
-		}
-		break
-	}
-	estimateJD := jde
-	for {
-		prevJD := estimateJD
-		rateValue := raRate(prevJD, 2.0/86400.0)
-		rateSlope := (raRate(prevJD+15.0/86400.0, 2.0/86400.0) - raRate(prevJD-15.0/86400.0, 2.0/86400.0)) / (30.0 / 86400.0)
-		estimateJD = prevJD - rateValue/rateSlope
-		if math.Abs(estimateJD-prevJD) <= 30.0/86400.0 {
-			break
-		}
-	}
-	bestJD := eventZeroRefine(estimateJD, 15.0/86400.0, 0.5/86400.0, func(jd float64) float64 {
-		return raRate(jd, 0.5/86400.0)
+	bestJD := zeroEventInWindow(startTT, endTT, 2.0, 2.0, 30.0/86400.0, func(jd float64) float64 {
+		return uranusRADerivativeN(jd, 1.0/86400.0, uranusEventSearchN)
+	}, func(jd float64) float64 {
+		return uranusRADerivative(jd, 0.5/86400.0)
 	})
 	return TD2UT(bestJD, false)
 }
 
 func NextUranusRetrogradeToPrograde(jde float64) float64 {
-	date := uranusRetrograde(jde, false)
-	if date < jde {
-		oppositionJD := uranusConjunctionFull(jde, 180, 1)
-		return uranusRetrograde(oppositionJD+10, false)
-	}
+	lastOppositionJD := uranusConjunctionFull(jde, 180, 0)
+	date := uranusRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryAfterOrEqual(date, jde) {
 		return date
+	}
+	nextOppositionJD := uranusConjunctionFull(jde, 180, 1)
+	return uranusRetrogradeAroundOpposition(nextOppositionJD, false)
 }
 
 func LastUranusRetrogradeToPrograde(jde float64) float64 {
-	jde = uranusConjunctionFull(jde, 180, 0) - 10
-	date := uranusRetrograde(jde, false)
-	if date > jde {
-		oppositionJD := uranusConjunctionFull(jde, 180, 0)
-		return uranusRetrograde(oppositionJD-10, false)
-	}
+	lastOppositionJD := uranusConjunctionFull(jde, 180, 0)
+	date := uranusRetrogradeAroundOpposition(lastOppositionJD, false)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryBeforeOrEqual(date, jde) {
 		return date
+	}
+	previousOppositionJD := uranusConjunctionFull(eventUTLastQueryTT(lastOppositionJD), 180, 0)
+	return uranusRetrogradeAroundOpposition(previousOppositionJD, false)
 }
 
 func NextUranusProgradeToRetrograde(jde float64) float64 {
-	date := uranusRetrograde(jde, true)
-	if date < jde {
-		oppositionJD := uranusConjunctionFull(jde, 180, 1)
-		return uranusRetrograde(oppositionJD+10, true)
-	}
+	nextOppositionJD := uranusConjunctionFull(jde, 180, 1)
+	date := uranusRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryAfterOrEqual(date, jde) {
 		return date
+	}
+	followingOppositionJD := uranusConjunctionFull(eventUTNextQueryTT(nextOppositionJD), 180, 1)
+	return uranusRetrogradeAroundOpposition(followingOppositionJD, true)
 }
 
 func LastUranusProgradeToRetrograde(jde float64) float64 {
-	jde = uranusConjunctionFull(jde, 180, 0) - 10
-	date := uranusRetrograde(jde, true)
-	if date > jde {
-		oppositionJD := uranusConjunctionFull(jde, 180, 0)
-		return uranusRetrograde(oppositionJD-10, true)
-	}
+	nextOppositionJD := uranusConjunctionFull(jde, 180, 1)
+	date := uranusRetrogradeAroundOpposition(nextOppositionJD, true)
+	if sameEventUTQueryTT(date, jde) || eventUTQueryBeforeOrEqual(date, jde) {
 		return date
+	}
+	lastOppositionJD := uranusConjunctionFull(jde, 180, 0)
+	return uranusRetrogradeAroundOpposition(lastOppositionJD, true)
 }

basic/venus.go

@@ -87,53 +87,22 @@ func VenusApparentRaDec(jd float64) (float64, float64) {
 }
 
 func EarthVenusAway(jd float64) float64 {
-	x, y, z := AVenusXYZ(jd)
-	to := math.Sqrt(x*x + y*y + z*z)
-	return to
+	return planetEarthAwayExplicitN(2, jd, -1)
 }
 
 func VenusApparentLo(jd float64) float64 {
-	x, y, z := AVenusXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AVenusXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo
+	geo, _ := planetApparentGeocentricPositionN(2, jd, -1)
+	return geo.lo
 }
 
 func VenusApparentBo(jd float64) float64 {
-	x, y, z := AVenusXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AVenusXYZ(jd - to)
-	//lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	//lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	//lo+=GXCLo(lo,bo,jd);
-	//bo+=GXCBo(lo,bo,jd)/3600;
-	//lo+=Nutation2000Bi(jd);
-	return bo
+	geo, _ := planetApparentGeocentricPositionN(2, jd, -1)
+	return geo.bo
 }
 
 func VenusApparentLoBo(jd float64) (float64, float64) {
-	x, y, z := AVenusXYZ(jd)
-	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
-	x, y, z = AVenusXYZ(jd - to)
-	lo := math.Atan2(y, x)
-	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
-	lo = lo * 180 / math.Pi
-	bo = bo * 180 / math.Pi
-	lo = Limit360(lo)
-	//lo-=GXCLo(lo,bo,jd)/3600;
-	//bo+=GXCBo(lo,bo,jd);
-	lo += Nutation2000Bi(jd)
-	return lo, bo
+	geo, _ := planetApparentGeocentricPositionN(2, jd, -1)
+	return geo.lo, geo.bo
 }
 
 func VenusMag(jd float64) float64 {

basic/venus_events.go

@@ -3,6 +3,7 @@ package basic
 import (
 	"math"
 
+	"b612.me/astro/planet"
 	. "b612.me/astro/tools"
 )
 
@@ -33,6 +34,23 @@ func venusSunLongitudeDeltaN(jde float64, n int) float64 {
 	return sub
 }
 
+func venusConjunctionAngleDelta(diff float64) float64 {
+	diff = Limit360(diff)
+	if diff > 180 {
+		diff -= 360
+	}
+	if diff < -180 {
+		diff += 360
+	}
+	return diff
+}
+
+func venusConjunctionHeliocentricDelta(jd, targetDeg float64, n int) float64 {
+	planetLo := planet.WherePlanetN(2, 0, jd, n)
+	earthLo := planet.WherePlanetN(-1, 0, jd, n)
+	return venusConjunctionAngleDelta(planetLo - earthLo - targetDeg)
+}
+
 func venusSunRADelta(jde float64) float64 {
 	sub := Limit360(VenusApparentRa(jde) - SunApparentRa(jde))
 	if sub > 180 {
@@ -66,13 +84,94 @@ func venusRADerivativeN(jde, val float64, n int) float64 {
 	return sub / (2 * val)
 }
 
+func venusRAContinuousForMax(jde float64) float64 {
+	ra := VenusApparentRa(jde)
+	if ra < 180 {
+		return ra + 360
+	}
+	return ra
+}
+
+func venusRAContinuousForMaxN(jde float64, n int) float64 {
+	ra := VenusApparentRaN(jde, n)
+	if ra < 180 {
+		return ra + 360
+	}
+	return ra
+}
+
+func venusRAContinuousForMin(jde float64) float64 {
+	ra := VenusApparentRa(jde)
+	if ra > 180 {
+		return ra - 360
+	}
+	return ra
+}
+
+func venusRAContinuousForMinN(jde float64, n int) float64 {
+	ra := VenusApparentRaN(jde, n)
+	if ra > 180 {
+		return ra - 360
+	}
+	return ra
+}
+
+func venusRAExtremumRefine(seed, start, end, step float64, fn func(float64) float64) float64 {
+	centerJD := clampFloat64(seed, start, end)
+	halfStep := step
+	bestJD := centerJD
+	bestVal := fn(centerJD)
+	for i := 0; i < 8; i++ {
+		leftJD := clampFloat64(centerJD-halfStep, start, end)
+		rightJD := clampFloat64(centerJD+halfStep, start, end)
+		leftVal := fn(leftJD)
+		centerVal := fn(centerJD)
+		rightVal := fn(rightJD)
+		if leftVal > bestVal {
+			bestVal = leftVal
+			bestJD = leftJD
+		}
+		if centerVal > bestVal {
+			bestVal = centerVal
+			bestJD = centerJD
+		}
+		if rightVal > bestVal {
+			bestVal = rightVal
+			bestJD = rightJD
+		}
+		denominator := leftVal - 2*centerVal + rightVal
+		if denominator == 0 {
+			centerJD = bestJD
+			halfStep /= 2
+			continue
+		}
+		vertexJD := centerJD + 0.5*halfStep*(leftVal-rightVal)/denominator
+		vertexJD = clampFloat64(vertexJD, leftJD, rightJD)
+		vertexVal := fn(vertexJD)
+		if vertexVal > bestVal {
+			bestVal = vertexVal
+			bestJD = vertexJD
+		}
+		centerJD = bestJD
+		halfStep /= 2
+	}
+	return bestJD
+}
+
 func venusSunElongationN(jde float64, n int) float64 {
 	lo1, bo1 := VenusApparentLoBoN(jde, n)
-	lo2 := SunApparentLo(jde)
+	lo2 := HSunApparentLoN(jde, n)
 	bo2 := HSunTrueBoN(jde, n)
 	return StarAngularSeparation(lo1, bo1, lo2, bo2)
 }
 
+func venusTrueElongationN(jde float64, n int) float64 {
+	earth := mercuryHelioN(-1, jde, n)
+	planetPos := mercuryHelioN(2, jde, n)
+	geo := mercuryGeocentric(planetPos, earth)
+	return StarAngularSeparation(geo.lo, geo.bo, HSunTrueLoN(jde, n), HSunTrueBoN(jde, n))
+}
+
 func venusElongationDerivative(jde, val float64) float64 {
 	sub := VenusSunElongation(jde+val) - VenusSunElongation(jde-val)
 	if sub > 180 {
@@ -96,91 +195,98 @@ func venusElongationDerivativeN(jde, val float64, n int) float64 {
 }
 
 func venusConjunction(jde float64, next uint8) float64 {
-	//0=last 1=next
-	nowSub := venusSunLongitudeDeltaN(jde, venusEventSearchN)
-	pos := math.Abs(venusSunLongitudeDeltaN(jde+1/86400.0, venusEventSearchN)) - math.Abs(nowSub)
-	if pos >= 0 && next == 1 && nowSub > 0 {
-		jde += VENUS_S_PERIOD/8.0 + 2
-	}
-	if pos >= 0 && next == 1 && nowSub < 0 {
-		jde += VENUS_S_PERIOD/6.0 + 2
-	}
-	if pos <= 0 && next == 0 && nowSub < 0 {
-		jde -= VENUS_S_PERIOD/8.0 + 2
-	}
-	if pos <= 0 && next == 0 && nowSub > 0 {
-		jde -= VENUS_S_PERIOD/6.0 + 2
-	}
-	for {
-		nowSub := venusSunLongitudeDeltaN(jde, venusEventSearchN)
-		pos := math.Abs(venusSunLongitudeDeltaN(jde+1/86400.0, venusEventSearchN)) - math.Abs(nowSub)
-		if math.Abs(nowSub) > 24 || (pos > 0 && next == 1) || (pos < 0 && next == 0) {
+	queryTT := jde
+	direction := -1.0
 	if next == 1 {
-				jde += 8
-			} else {
-				jde -= 8
+		direction = 1
 	}
-			continue
-		}
-		break
-	}
-	JD1 := jde
-	for {
-		JD0 := JD1
-		stDegree := venusSunLongitudeDelta(JD0)
-		stDegreep := (venusSunLongitudeDelta(JD0+0.000005) - venusSunLongitudeDelta(JD0-0.000005)) / 0.00001
-		JD1 = JD0 - stDegree/stDegreep
-		if math.Abs(JD1-JD0) <= 0.00001 {
-			break
+	left := queryTT
+	leftVal := venusSunLongitudeDeltaN(left, venusEventSearchN)
+	if math.Abs(leftVal) <= 30.0/86400.0 {
+		exact := eventZeroRefine(left, 1.0, 0.000005, venusSunLongitudeDelta)
+		if math.Abs(exact-queryTT) <= 1.0 {
+			return TD2UT(exact, false)
 		}
 	}
-	return TD2UT(JD1, false)
+	const step = 8.0
+	for i := 0; i < 80; i++ {
+		right := queryTT + direction*step*float64(i+1)
+		rightVal := venusSunLongitudeDeltaN(right, venusEventSearchN)
+		if leftVal == 0 || rightVal == 0 || leftVal*rightVal <= 0 {
+			center := (left + right) / 2.0
+			halfWindow := math.Abs(right-left) / 2.0
+			return TD2UT(eventZeroRefine(center, halfWindow, 0.000005, venusSunLongitudeDelta), false)
+		}
+		left = right
+		leftVal = rightVal
+	}
+	return TD2UT(eventZeroRefine(queryTT, VENUS_S_PERIOD, 0.000005, venusSunLongitudeDelta), false)
+}
+
+func venusConjunctionTypeAt(eventUT float64) bool {
+	return EarthVenusAway(eventUT) <= EarthAway(eventUT)
+}
+
+func nextVenusTypedConjunctionFromEvent(jde float64, inferior bool) float64 {
+	date := NextVenusConjunctionStrict(jde)
+	if venusConjunctionTypeAt(date) == inferior {
+		return date
+	}
+	return NextVenusConjunctionStrict(eventUTNextQueryTT(date))
+}
+
+func lastVenusTypedConjunctionFromEvent(jde float64, inferior bool) float64 {
+	date := LastVenusConjunctionStrict(jde)
+	if venusConjunctionTypeAt(date) == inferior {
+		return date
+	}
+	return LastVenusConjunctionStrict(eventUTLastQueryTT(date))
 }
 
 func LastVenusConjunction(jde float64) float64 {
-	return venusConjunction(jde, 0)
+	return inclusiveLastSimpleEvent(jde, LastVenusConjunctionStrict, NextVenusConjunctionStrict)
 }
 
 func NextVenusConjunction(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastVenusConjunctionStrict, NextVenusConjunctionStrict)
+}
+
+func LastVenusConjunctionStrict(jde float64) float64 {
+	return venusConjunction(jde, 0)
+}
+
+func NextVenusConjunctionStrict(jde float64) float64 {
 	return venusConjunction(jde, 1)
 }
 
+func nextVenusTypedConjunction(jde float64, inferior bool) float64 {
+	return nextVenusTypedConjunctionFromEvent(jde, inferior)
+}
+
+func lastVenusTypedConjunction(jde float64, inferior bool) float64 {
+	return lastVenusTypedConjunctionFromEvent(jde, inferior)
+}
+
 func NextVenusInferiorConjunction(jde float64) float64 {
-	date := NextVenusConjunction(jde)
-	if EarthVenusAway(date) > EarthAway(date) {
-		return NextVenusConjunction(date + 2)
-	}
-	return date
+	return nextVenusTypedConjunction(jde, true)
 }
 
 func NextVenusSuperiorConjunction(jde float64) float64 {
-	date := NextVenusConjunction(jde)
-	if EarthVenusAway(date) < EarthAway(date) {
-		return NextVenusConjunction(date + 2)
-	}
-	return date
+	return nextVenusTypedConjunction(jde, false)
 }
 
 func LastVenusInferiorConjunction(jde float64) float64 {
-	date := LastVenusConjunction(jde)
-	if EarthVenusAway(date) > EarthAway(date) {
-		return LastVenusConjunction(date - 2)
-	}
-	return date
+	return lastVenusTypedConjunction(jde, true)
 }
 
 func LastVenusSuperiorConjunction(jde float64) float64 {
-	date := LastVenusConjunction(jde)
-	if EarthVenusAway(date) < EarthAway(date) {
-		return LastVenusConjunction(date - 2)
-	}
-	return date
+	return lastVenusTypedConjunction(jde, false)
 }
 
 func venusRetrograde(jde float64) float64 {
 	//0=last 1=next
-	lastHe := LastVenusConjunction(jde)
-	nextHe := NextVenusConjunction(jde)
+	lastHe := LastVenusConjunctionStrict(jde)
+	nextHe := NextVenusConjunctionStrict(jde)
 	nowSub := venusSunRADelta(jde)
 	if nowSub > 0 {
 		jde = lastHe + ((nextHe - lastHe) / 5.0 * 3.5)
@@ -213,152 +319,317 @@ func venusRetrograde(jde float64) float64 {
 }
 
 func NextVenusRetrograde(jde float64) float64 {
-	date := venusRetrograde(jde)
-	if date < jde {
-		nextHe := NextVenusConjunction(jde)
-		return venusRetrograde(nextHe + 2)
+	p2r := NextVenusProgradeToRetrograde(jde)
+	r2p := NextVenusRetrogradeToPrograde(jde)
+	if sameEventJD(p2r, r2p) {
+		return p2r
 	}
-	return date
+	if p2r < r2p {
+		return p2r
+	}
+	return r2p
 }
 
 func LastVenusRetrograde(jde float64) float64 {
-	lastHe := LastVenusConjunction(jde)
-	date := venusRetrograde(lastHe + 2)
-	if date > jde {
-		lastLastHe := LastVenusConjunction(lastHe - 2)
-		return venusRetrograde(lastLastHe + 2)
+	p2r := LastVenusProgradeToRetrograde(jde)
+	r2p := LastVenusRetrogradeToPrograde(jde)
+	if sameEventJD(p2r, r2p) {
+		return p2r
 	}
-	return date
+	if p2r > r2p {
+		return p2r
+	}
+	return r2p
+}
+
+func venusStationInWindow(start, end float64, progradeToRetrograde bool) float64 {
+	var best float64
+	if progradeToRetrograde {
+		guess := scanWindowForMax(start, end, 2.0, func(jd float64) float64 {
+			return venusRAContinuousForMaxN(jd, venusEventSearchN)
+		})
+		best = venusRAExtremumRefine(guess, start, end, 1.0, func(jd float64) float64 {
+			return venusRAContinuousForMax(jd)
+		})
+	} else {
+		guess := scanWindowForMax(start, end, 2.0, func(jd float64) float64 {
+			return -venusRAContinuousForMinN(jd, venusEventSearchN)
+		})
+		best = venusRAExtremumRefine(guess, start, end, 1.0, func(jd float64) float64 {
+			return -venusRAContinuousForMin(jd)
+		})
+	}
+	return TD2UT(best, false)
+}
+
+func venusProgradeToRetrogradeAroundInferior(inferior float64) float64 {
+	return venusStationInWindow(inferior-30.0, inferior-14.0, true)
+}
+
+func venusRetrogradeToProgradeAroundInferior(inferior float64) float64 {
+	return venusStationInWindow(inferior+14.0, inferior+24.0, false)
 }
 
 func NextVenusProgradeToRetrograde(jde float64) float64 {
-	date := NextVenusRetrograde(jde)
-	sub := Limit360(VenusApparentRa(date) - SunApparentRa(date))
-	if sub > 180 {
-		return NextVenusRetrograde(date + VENUS_S_PERIOD/2)
-	}
+	inferior := NextVenusInferiorConjunction(jde)
+	for {
+		date := venusProgradeToRetrogradeAroundInferior(inferior)
+		if eventUTQueryAfterOrEqual(date, jde) {
 			return date
+		}
+		inferior = NextVenusInferiorConjunction(eventUTNextQueryTT(inferior))
+	}
 }
 
 func NextVenusRetrogradeToPrograde(jde float64) float64 {
-	date := NextVenusRetrograde(jde)
-	sub := Limit360(VenusApparentRa(date) - SunApparentRa(date))
-	if sub < 180 {
-		return NextVenusRetrograde(date + 12)
-	}
+	inferior := LastVenusInferiorConjunction(jde)
+	for {
+		date := venusRetrogradeToProgradeAroundInferior(inferior)
+		if eventUTQueryAfterOrEqual(date, jde) {
 			return date
+		}
+		inferior = NextVenusInferiorConjunction(eventUTNextQueryTT(inferior))
+	}
 }
 
 func LastVenusProgradeToRetrograde(jde float64) float64 {
-	date := LastVenusRetrograde(jde)
-	sub := Limit360(VenusApparentRa(date) - SunApparentRa(date))
-	if sub > 180 {
-		return LastVenusRetrograde(date - 12)
-	}
+	inferior := NextVenusInferiorConjunction(jde)
+	for {
+		date := venusProgradeToRetrogradeAroundInferior(inferior)
+		if eventUTQueryBeforeOrEqual(date, jde) {
 			return date
+		}
+		inferior = LastVenusInferiorConjunction(eventUTLastQueryTT(inferior))
+	}
 }
 
 func LastVenusRetrogradeToPrograde(jde float64) float64 {
-	date := LastVenusRetrograde(jde)
-	sub := Limit360(VenusApparentRa(date) - SunApparentRa(date))
-	if sub < 180 {
-		return LastVenusRetrograde(date - VENUS_S_PERIOD/2)
-	}
+	inferior := LastVenusInferiorConjunction(jde)
+	for {
+		date := venusRetrogradeToProgradeAroundInferior(inferior)
+		if eventUTQueryBeforeOrEqual(date, jde) {
 			return date
+		}
+		inferior = LastVenusInferiorConjunction(eventUTLastQueryTT(inferior))
+	}
 }
 
 func VenusSunElongation(jde float64) float64 {
 	lo1, bo1 := VenusApparentLoBo(jde)
-	lo2 := SunApparentLo(jde)
+	lo2 := HSunApparentLo(jde)
 	bo2 := HSunTrueBo(jde)
 	return StarAngularSeparation(lo1, bo1, lo2, bo2)
 }
 
-func venusGreatestElongation(jde float64) float64 {
-	lastHe := LastVenusConjunction(jde)
-	nextHe := NextVenusConjunction(jde)
-	nowSub := venusSunRADelta(jde)
-	if nowSub > 0 {
-		jde = lastHe + ((nextHe - lastHe) / 5.0 * 2.5)
-	} else {
-		jde = lastHe + ((nextHe - lastHe) / 5.0)
-	}
-	for {
-		nowSub := venusElongationDerivativeN(jde, 1.0/86400.0, venusEventSearchN)
-		if math.Abs(nowSub) > 0.15 {
-			jde += 5
-			continue
-		}
-		break
-	}
-	JD1 := jde
-	for {
-		JD0 := JD1
-		stDegree := venusElongationDerivative(JD0, 2.0/86400.0)
-		stDegreep := (venusElongationDerivative(JD0+15.0/86400.0, 2.0/86400.0) - venusElongationDerivative(JD0-15.0/86400.0, 2.0/86400.0)) / (30.0 / 86400.0)
-		JD1 = JD0 - stDegree/stDegreep
-		if math.Abs(JD1-JD0) <= 30.0/86400.0 {
-			break
-		}
-	}
-	min := eventZeroRefine(JD1, 15.0/86400.0, 0.5/86400.0, func(jd float64) float64 {
-		return venusElongationDerivative(jd, 0.5/86400.0)
+func venusGreatestElongationInWindow(start, end float64) float64 {
+	best := maximizeInWindow(start, end, 5.0, func(jd float64) float64 {
+		return venusTrueElongationN(jd, venusEventSearchN)
+	}, func(jd float64) float64 {
+		return venusTrueElongationN(jd, -1)
 	})
-	//fmt.Println((min - lastHe) / (nextHe - lastHe))
-	return TD2UT(min, false)
+	return TD2UT(best, false)
+}
+
+func venusEastElongationWindowEndingAt(inferior float64) (float64, float64) {
+	lastSuperior := LastVenusSuperiorConjunction(eventUTLastQueryTT(inferior))
+	return lastSuperior + innerEventEpsilon, inferior - innerEventEpsilon
+}
+
+func venusWestElongationWindowEndingAt(superior float64) (float64, float64) {
+	lastInferior := LastVenusInferiorConjunction(eventUTLastQueryTT(superior))
+	return lastInferior + innerEventEpsilon, superior - innerEventEpsilon
+}
+
+func venusEastElongationWindowContaining(jde float64) (float64, float64) {
+	nextInferior := NextVenusInferiorConjunction(jde)
+	start, end := venusEastElongationWindowEndingAt(nextInferior)
+	if eventUTQueryBeforeOrEqual(start, jde) && eventUTQueryAfterOrEqual(end, jde) {
+		return start, end
+	}
+	currentInferior := LastVenusInferiorConjunction(jde)
+	return venusEastElongationWindowEndingAt(currentInferior)
+}
+
+func venusWestElongationWindowContaining(jde float64) (float64, float64) {
+	nextSuperior := NextVenusSuperiorConjunction(jde)
+	start, end := venusWestElongationWindowEndingAt(nextSuperior)
+	if eventUTQueryBeforeOrEqual(start, jde) && eventUTQueryAfterOrEqual(end, jde) {
+		return start, end
+	}
+	currentSuperior := LastVenusSuperiorConjunction(jde)
+	return venusWestElongationWindowEndingAt(currentSuperior)
+}
+
+func nextVenusGreatestElongationTyped(jde float64, east bool) float64 {
+	if east {
+		start, windowEnd := venusEastElongationWindowContaining(jde)
+		for {
+			date := venusGreatestElongationInWindow(start, windowEnd)
+			if eventUTQueryAfterOrEqual(date, jde) {
+				return date
+			}
+			nextInferior := NextVenusInferiorConjunction(eventUTNextQueryTT(windowEnd))
+			start, windowEnd = venusEastElongationWindowEndingAt(nextInferior)
+		}
+	}
+	start, windowEnd := venusWestElongationWindowContaining(jde)
+	for {
+		date := venusGreatestElongationInWindow(start, windowEnd)
+		if eventUTQueryAfterOrEqual(date, jde) {
+			return date
+		}
+		nextSuperior := NextVenusSuperiorConjunction(eventUTNextQueryTT(windowEnd))
+		start, windowEnd = venusWestElongationWindowEndingAt(nextSuperior)
+	}
+}
+
+func lastVenusGreatestElongationTyped(jde float64, east bool) float64 {
+	if east {
+		start, windowEnd := venusEastElongationWindowContaining(jde)
+		for {
+			date := venusGreatestElongationInWindow(start, windowEnd)
+			if eventUTQueryBeforeOrEqual(date, jde) {
+				return date
+			}
+			prevInferior := LastVenusInferiorConjunction(eventUTLastQueryTT(start))
+			start, windowEnd = venusEastElongationWindowEndingAt(prevInferior)
+		}
+	}
+	start, windowEnd := venusWestElongationWindowContaining(jde)
+	for {
+		date := venusGreatestElongationInWindow(start, windowEnd)
+		if eventUTQueryBeforeOrEqual(date, jde) {
+			return date
+		}
+		prevSuperior := LastVenusSuperiorConjunction(eventUTLastQueryTT(start))
+		start, windowEnd = venusWestElongationWindowEndingAt(prevSuperior)
+	}
+}
+
+func venusGreatestElongation(jde float64) float64 {
+	east := venusSunRADelta(jde) > 0
+	if east {
+		return nextVenusGreatestElongationTyped(jde, true)
+	}
+	return nextVenusGreatestElongationTyped(jde, false)
 }
 
 func NextVenusGreatestElongation(jde float64) float64 {
-	date := venusGreatestElongation(jde)
-	if date < jde {
-		nextHe := NextVenusConjunction(jde)
-		return venusGreatestElongation(nextHe + 2)
+	east := NextVenusGreatestElongationEast(jde)
+	west := NextVenusGreatestElongationWest(jde)
+	if sameEventJD(east, west) {
+		return east
 	}
-	return date
+	if east < west {
+		return east
+	}
+	return west
 }
 
 func LastVenusGreatestElongation(jde float64) float64 {
-	lastHe := LastVenusConjunction(jde)
-	date := venusGreatestElongation(lastHe + 2)
-	if date > jde {
-		lastLastHe := LastVenusConjunction(lastHe - 2)
-		return venusGreatestElongation(lastLastHe + 2)
+	east := LastVenusGreatestElongationEast(jde)
+	west := LastVenusGreatestElongationWest(jde)
+	if sameEventJD(east, west) {
+		return east
 	}
+	if east > west {
+		return east
+	}
+	return west
+}
+
+func LastVenusInferiorConjunctionInclusive(jde float64) float64 {
+	date := LastVenusConjunction(jde)
+	if venusConjunctionTypeAt(date) {
 		return date
+	}
+	return LastVenusConjunction(eventUTLastQueryTT(date))
+}
+
+func NextVenusInferiorConjunctionInclusive(jde float64) float64 {
+	date := NextVenusConjunction(jde)
+	if venusConjunctionTypeAt(date) {
+		return date
+	}
+	return NextVenusConjunction(eventUTNextQueryTT(date))
+}
+
+func LastVenusSuperiorConjunctionInclusive(jde float64) float64 {
+	date := LastVenusConjunction(jde)
+	if !venusConjunctionTypeAt(date) {
+		return date
+	}
+	return LastVenusConjunction(eventUTLastQueryTT(date))
+}
+
+func NextVenusSuperiorConjunctionInclusive(jde float64) float64 {
+	date := NextVenusConjunction(jde)
+	if !venusConjunctionTypeAt(date) {
+		return date
+	}
+	return NextVenusConjunction(eventUTNextQueryTT(date))
+}
+
+func LastVenusRetrogradeInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastVenusRetrograde, NextVenusRetrograde)
+}
+
+func NextVenusRetrogradeInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastVenusRetrograde, NextVenusRetrograde)
+}
+
+func LastVenusProgradeToRetrogradeInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastVenusProgradeToRetrograde, NextVenusProgradeToRetrograde)
+}
+
+func NextVenusProgradeToRetrogradeInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastVenusProgradeToRetrograde, NextVenusProgradeToRetrograde)
+}
+
+func LastVenusRetrogradeToProgradeInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastVenusRetrogradeToPrograde, NextVenusRetrogradeToPrograde)
+}
+
+func NextVenusRetrogradeToProgradeInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastVenusRetrogradeToPrograde, NextVenusRetrogradeToPrograde)
+}
+
+func LastVenusGreatestElongationInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastVenusGreatestElongation, NextVenusGreatestElongation)
+}
+
+func NextVenusGreatestElongationInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastVenusGreatestElongation, NextVenusGreatestElongation)
+}
+
+func LastVenusGreatestElongationEastInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastVenusGreatestElongationEast, NextVenusGreatestElongationEast)
+}
+
+func NextVenusGreatestElongationEastInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastVenusGreatestElongationEast, NextVenusGreatestElongationEast)
+}
+
+func LastVenusGreatestElongationWestInclusive(jde float64) float64 {
+	return inclusiveLastSimpleEvent(jde, LastVenusGreatestElongationWest, NextVenusGreatestElongationWest)
+}
+
+func NextVenusGreatestElongationWestInclusive(jde float64) float64 {
+	return inclusiveNextSimpleEvent(jde, LastVenusGreatestElongationWest, NextVenusGreatestElongationWest)
 }
 
 func NextVenusGreatestElongationEast(jde float64) float64 {
-	date := NextVenusGreatestElongation(jde)
-	sub := Limit360(VenusApparentRa(date) - SunApparentRa(date))
-	if sub > 180 {
-		return NextVenusGreatestElongation(date + 1)
-	}
-	return date
+	return nextVenusGreatestElongationTyped(jde, true)
 }
 
 func NextVenusGreatestElongationWest(jde float64) float64 {
-	date := NextVenusGreatestElongation(jde)
-	sub := Limit360(VenusApparentRa(date) - SunApparentRa(date))
-	if sub < 180 {
-		return NextVenusGreatestElongation(date + 1)
-	}
-	return date
+	return nextVenusGreatestElongationTyped(jde, false)
 }
 
 func LastVenusGreatestElongationEast(jde float64) float64 {
-	date := LastVenusGreatestElongation(jde)
-	sub := Limit360(VenusApparentRa(date) - SunApparentRa(date))
-	if sub > 180 {
-		return LastVenusGreatestElongation(date - 1)
-	}
-	return date
+	return lastVenusGreatestElongationTyped(jde, true)
 }
 
 func LastVenusGreatestElongationWest(jde float64) float64 {
-	date := LastVenusGreatestElongation(jde)
-	sub := Limit360(VenusApparentRa(date) - SunApparentRa(date))
-	if sub < 180 {
-		return LastVenusGreatestElongation(date - 1)
-	}
-	return date
+	return lastVenusGreatestElongationTyped(jde, false)
 }

eclipse/lunar.go

@@ -279,7 +279,7 @@ func searchLunarEclipse(
 				return lunarEclipseInfoFromBasic(result, date.Location()), true
 			}
 		}
-		candidateTT = basic.CalcMoonSHByJDE(candidateTT+float64(direction)*lunarEclipseSynodicMonthDays, 1)
+		candidateTT = nextEclipseSearchCandidateTT(candidateTT, 1, direction, lunarEclipseSynodicMonthDays)
 	}
 
 	return LunarEclipseInfo{}, false

eclipse/lunar_local.go

@@ -147,6 +147,12 @@ func LastLocalLunarEclipse(date time.Time, lon, lat, height float64) LocalLunarE
 	return LastLocalLunarEclipseDanjon(date, lon, lat, height)
 }
 
+// LastLocalTotalLunarEclipse 上次可见月全食 / previous visible local total lunar eclipse.
+// Previous visible local total lunar eclipse, using Danjon by default.
+func LastLocalTotalLunarEclipse(date time.Time, lon, lat, height float64) (LocalLunarEclipseInfo, bool) {
+	return searchLocalTotalLunarEclipse(date, lon, lat, height, -1, true, basic.LunarEclipseDanjon, localLunarEclipseQueryVisible)
+}
+
 // LastLocalLunarEclipseDanjon 上次可见月食（Danjon） / previous visible local lunar eclipse with Danjon model.
 // Previous visible local lunar eclipse with the Danjon model.
 func LastLocalLunarEclipseDanjon(date time.Time, lon, lat, height float64) LocalLunarEclipseInfo {
@@ -187,6 +193,12 @@ func NextLocalLunarEclipse(date time.Time, lon, lat, height float64) LocalLunarE
 	return NextLocalLunarEclipseDanjon(date, lon, lat, height)
 }
 
+// NextLocalTotalLunarEclipse 下次可见月全食 / next visible local total lunar eclipse.
+// Next visible local total lunar eclipse, using Danjon by default.
+func NextLocalTotalLunarEclipse(date time.Time, lon, lat, height float64) (LocalLunarEclipseInfo, bool) {
+	return searchLocalTotalLunarEclipse(date, lon, lat, height, 1, false, basic.LunarEclipseDanjon, localLunarEclipseQueryVisible)
+}
+
 // NextLocalLunarEclipseDanjon 下次可见月食（Danjon） / next visible local lunar eclipse with Danjon model.
 // Next visible local lunar eclipse with the Danjon model.
 func NextLocalLunarEclipseDanjon(date time.Time, lon, lat, height float64) LocalLunarEclipseInfo {
@@ -227,6 +239,14 @@ func ClosestLocalLunarEclipse(date time.Time, lon, lat, height float64) LocalLun
 	return ClosestLocalLunarEclipseDanjon(date, lon, lat, height)
 }
 
+// ClosestLocalTotalLunarEclipse 最近一次可见月全食 / closest visible local total lunar eclipse.
+// Closest visible local total lunar eclipse, using Danjon by default.
+func ClosestLocalTotalLunarEclipse(date time.Time, lon, lat, height float64) (LocalLunarEclipseInfo, bool) {
+	last, hasLast := searchLocalTotalLunarEclipse(date, lon, lat, height, -1, true, basic.LunarEclipseDanjon, localLunarEclipseQueryVisible)
+	next, hasNext := searchLocalTotalLunarEclipse(date, lon, lat, height, 1, false, basic.LunarEclipseDanjon, localLunarEclipseQueryVisible)
+	return closestLocalLunarEclipseResult(date, last, hasLast, next, hasNext)
+}
+
 // ClosestLocalLunarEclipseDanjon 最近一次可见月食（Danjon） / closest visible local lunar eclipse with Danjon model.
 // Closest visible local lunar eclipse with the Danjon model.
 func ClosestLocalLunarEclipseDanjon(date time.Time, lon, lat, height float64) LocalLunarEclipseInfo {
@@ -272,21 +292,32 @@ func closestLocalLunarEclipse(
 	next LocalLunarEclipseInfo,
 	hasNext bool,
 ) LocalLunarEclipseInfo {
+	info, _ := closestLocalLunarEclipseResult(date, last, hasLast, next, hasNext)
+	return info
+}
+
+func closestLocalLunarEclipseResult(
+	date time.Time,
+	last LocalLunarEclipseInfo,
+	hasLast bool,
+	next LocalLunarEclipseInfo,
+	hasNext bool,
+) (LocalLunarEclipseInfo, bool) {
 	switch {
 	case hasLast && !hasNext:
-		return last
+		return last, true
 	case !hasLast && hasNext:
-		return next
+		return next, true
 	case !hasLast && !hasNext:
-		return LocalLunarEclipseInfo{}
+		return LocalLunarEclipseInfo{}, false
 	}
 
 	lastDistance := math.Abs(date.Sub(last.Maximum).Seconds())
 	nextDistance := math.Abs(next.Maximum.Sub(date).Seconds())
 	if lastDistance <= nextDistance {
-		return last
+		return last, true
 	}
-	return next
+	return next, true
 }
 
 func searchLocalLunarEclipse(
@@ -311,7 +342,35 @@ func searchLocalLunarEclipse(
 				}
 			}
 		}
-		candidateTT = basic.CalcMoonSHByJDE(candidateTT+float64(direction)*lunarEclipseSynodicMonthDays, 1)
+		candidateTT = nextEclipseSearchCandidateTT(candidateTT, 1, direction, lunarEclipseSynodicMonthDays)
+	}
+
+	return LocalLunarEclipseInfo{}, false
+}
+
+func searchLocalTotalLunarEclipse(
+	date time.Time,
+	lon, lat, height float64,
+	direction int,
+	includeCurrent bool,
+	calculator lunarEclipseCalculator,
+	mode localLunarEclipseQueryMode,
+) (LocalLunarEclipseInfo, bool) {
+	targetTT := timeToTTJDE(date)
+	candidateTT := basic.CalcMoonSHByJDE(targetTT, 1)
+
+	for i := 0; i < localLunarEclipseSearchLimit; i++ {
+		if isPotentialLunarEclipse(candidateTT) {
+			result := calculator(candidateTT)
+			if result.HasTotal {
+				info := localLunarEclipseInfoFromBasic(result, lon, lat, height, date.Location())
+				if (mode != localLunarEclipseQueryVisible || localTotalLunarEclipseVisible(info)) &&
+					lunarEclipseMatchesDirection(result.Maximum, targetTT, direction, includeCurrent) {
+					return info, true
+				}
+			}
+		}
+		candidateTT = nextEclipseSearchCandidateTT(candidateTT, 1, direction, lunarEclipseSynodicMonthDays)
 	}
 
 	return LocalLunarEclipseInfo{}, false
@@ -375,6 +434,13 @@ func localLunarEclipseVisible(info LocalLunarEclipseInfo) bool {
 	return localLunarEclipseVisibleDuring(info, eventStart, eventEnd)
 }
 
+func localTotalLunarEclipseVisible(info LocalLunarEclipseInfo) bool {
+	if !info.HasTotal || info.TotalStart.IsZero() || info.TotalEnd.IsZero() {
+		return false
+	}
+	return localLunarEclipseVisibleDuring(info, info.TotalStart, info.TotalEnd)
+}
+
 func localLunarEclipseVisibleOnDate(info LocalLunarEclipseInfo, dayStart, dayEnd time.Time) bool {
 	eventStart, eventEnd, ok := localLunarEclipseRange(info)
 	if !ok {

eclipse/lunar_local_test.go

@@ -133,6 +133,61 @@ func TestLocalLunarEclipseSearchBeyondFiveYears(t *testing.T) {
 	}
 }
 
+func TestLocalTotalLunarEclipseSearch(t *testing.T) {
+	loc := time.FixedZone("CDT", -5*3600)
+	lon, lat, height := -87.65, 41.85, 0.0
+	date := time.Date(2025, 3, 13, 0, 0, 0, 0, loc)
+
+	next, ok := NextLocalTotalLunarEclipse(date, lon, lat, height)
+	if !ok {
+		t.Fatal("expected to find next local total lunar eclipse")
+	}
+	if next.Type != LunarEclipseTotal || !next.HasTotal {
+		t.Fatalf("unexpected next total lunar eclipse: %+v", next)
+	}
+	assertTimeClose(t, "NextLocalTotalLunarEclipse", next.Maximum, time.Date(2025, 3, 14, 1, 58, 47, 0, loc), 2*time.Minute)
+
+	last, ok := LastLocalTotalLunarEclipse(next.Maximum, lon, lat, height)
+	if !ok {
+		t.Fatal("expected to find previous local total lunar eclipse")
+	}
+	if last.Type != LunarEclipseTotal || !last.HasTotal {
+		t.Fatalf("unexpected last total lunar eclipse: %+v", last)
+	}
+	assertTimeClose(t, "LastLocalTotalLunarEclipse", last.Maximum, next.Maximum, time.Second)
+}
+
+func TestLocalTotalLunarEclipseClosest(t *testing.T) {
+	loc := time.FixedZone("CDT", -5*3600)
+	lon, lat, height := -87.65, 41.85, 0.0
+	date := time.Date(2025, 3, 14, 0, 0, 0, 0, loc)
+
+	info, ok := ClosestLocalTotalLunarEclipse(date, lon, lat, height)
+	if !ok {
+		t.Fatal("expected to find closest local total lunar eclipse")
+	}
+	if info.Type != LunarEclipseTotal || !info.HasTotal {
+		t.Fatalf("unexpected closest total lunar eclipse: %+v", info)
+	}
+	assertTimeClose(t, "ClosestLocalTotalLunarEclipse", info.Maximum, time.Date(2025, 3, 14, 1, 58, 47, 0, loc), 2*time.Minute)
+}
+
+func TestLocalTotalLunarEclipseVisibleRequiresTotalPhaseVisibility(t *testing.T) {
+	info, ok := LocalLunarEclipseOnDate(time.Date(2025, 3, 14, 12, 0, 0, 0, time.UTC), -0.1278, 51.5074, 0)
+	if !ok {
+		t.Fatalf("expected visible local eclipse in London")
+	}
+	if info.Type != LunarEclipseTotal || !info.HasTotal {
+		t.Fatalf("unexpected eclipse type: %+v", info)
+	}
+	if !localLunarEclipseVisible(info) {
+		t.Fatalf("expected some phase to be visible")
+	}
+	if localTotalLunarEclipseVisible(info) {
+		t.Fatalf("expected total phase below horizon to be rejected")
+	}
+}
+
 func TestLocalLunarEclipseInfoKeepsLocation(t *testing.T) {
 	loc := time.FixedZone("JST", 9*3600)
 	lon, lat, height := 139.6917, 35.6895, 1234.0

eclipse/saros.go

@@ -1,6 +1,7 @@
 package eclipse
 
 import (
+	"math"
 	"time"
 
 	"b612.me/astro/basic"
@@ -10,6 +11,18 @@ const (
 	sarosCycleLunations = 223
 	sarosCycleDays      = float64(sarosCycleLunations) * solarEclipseSynodicMonthDays
 	sarosWalkLimit      = 100
+
+	sarosMagicYearOffset    = 3000
+	sarosMagicCountMask     = 0x7f
+	sarosMagicDayMask       = 0x1f
+	sarosMagicMonthMask     = 0x0f
+	sarosMagicYearMask      = 0x1fff
+	sarosMagicCountShift    = 0
+	sarosMagicDayShift      = 7
+	sarosMagicMonthShift    = 12
+	sarosMagicYearShift     = 16
+	sarosMagicMatchLimitDay = 12.0
+	sarosMagicTieEpsilonDay = 1e-9
 )
 
 // SarosInfo 沙罗序列信息, Saros series metadata.
@@ -25,6 +38,8 @@ type SarosInfo struct {
 	Count int
 }
 
+type sarosMagic uint32
+
 type sarosAnchor struct {
 	Series int16
 	Count  uint8
@@ -53,6 +68,20 @@ var lunarSarosHeadOverrides = [...]sarosHeadOverride{
 }
 
 func solarSarosInfo(ttJDE float64) (SarosInfo, bool) {
+	if info, ok := matchSarosMagic(solarSarosAnchors[:], 0, solarSarosHeadOverrides[:], ttJDE); ok {
+		return info, true
+	}
+	return solarSarosInfoByWalk(ttJDE)
+}
+
+func lunarSarosInfo(ttJDE float64) (SarosInfo, bool) {
+	if info, ok := matchSarosMagic(lunarSarosAnchors[:], 1, lunarSarosHeadOverrides[:], ttJDE); ok {
+		return info, true
+	}
+	return lunarSarosInfoByWalk(ttJDE)
+}
+
+func solarSarosInfoByWalk(ttJDE float64) (SarosInfo, bool) {
 	headTT, member, ok := solarSarosHead(ttJDE)
 	if !ok {
 		return SarosInfo{}, false
@@ -60,7 +89,7 @@ func solarSarosInfo(ttJDE float64) (SarosInfo, bool) {
 	if info, ok := matchSarosHeadOverride(solarSarosHeadOverrides[:], headTT, member); ok {
 		return info, true
 	}
-	anchor, ok := matchSarosAnchor(solarSarosAnchors[:], headTT)
+	anchor, ok := matchSarosAnchor(solarSarosAnchors[:], 0, headTT)
 	if !ok || member > int(anchor.Count) {
 		return SarosInfo{}, false
 	}
@@ -71,7 +100,7 @@ func solarSarosInfo(ttJDE float64) (SarosInfo, bool) {
 	}, true
 }
 
-func lunarSarosInfo(ttJDE float64) (SarosInfo, bool) {
+func lunarSarosInfoByWalk(ttJDE float64) (SarosInfo, bool) {
 	headTT, member, ok := lunarSarosHead(ttJDE)
 	if !ok {
 		return SarosInfo{}, false
@@ -79,7 +108,7 @@ func lunarSarosInfo(ttJDE float64) (SarosInfo, bool) {
 	if info, ok := matchSarosHeadOverride(lunarSarosHeadOverrides[:], headTT, member); ok {
 		return info, true
 	}
-	anchor, ok := matchSarosAnchor(lunarSarosAnchors[:], headTT)
+	anchor, ok := matchSarosAnchor(lunarSarosAnchors[:], 1, headTT)
 	if !ok || member > int(anchor.Count) {
 		return SarosInfo{}, false
 	}
@@ -120,11 +149,102 @@ func lunarSarosHead(ttJDE float64) (float64, int, bool) {
 	return 0, 0, false
 }
 
-func matchSarosAnchor(anchors []sarosAnchor, headTT float64) (sarosAnchor, bool) {
+func matchSarosMagic(anchors []sarosMagic, seriesBase int, overrides []sarosHeadOverride, ttJDE float64) (SarosInfo, bool) {
+	if info, ok := matchSarosMagicOverrides(overrides, ttJDE); ok {
+		return info, true
+	}
+	bestDistance := math.Inf(1)
+	best := SarosInfo{}
+	for index, magic := range anchors {
+		anchor := decodeSarosMagic(magic, seriesBase+index)
+		info, distance, ok := matchSarosMagicCandidate(ttJDE, anchor, 0)
+		if !ok {
+			continue
+		}
+		if betterSarosMagicMatch(info, distance, best, bestDistance) {
+			bestDistance = distance
+			best = info
+		}
+	}
+	if bestDistance <= sarosMagicMatchLimitDay {
+		return best, true
+	}
+	return SarosInfo{}, false
+}
+
+func matchSarosMagicOverrides(overrides []sarosHeadOverride, ttJDE float64) (SarosInfo, bool) {
+	bestDistance := math.Inf(1)
+	best := SarosInfo{}
+	for _, override := range overrides {
+		anchor := sarosAnchor{
+			Series: override.Series,
+			Count:  override.Count,
+			Year:   override.HeadYear,
+			Month:  override.HeadMonth,
+			Day:    override.HeadDay,
+		}
+		info, distance, ok := matchSarosMagicCandidate(ttJDE, anchor, int(override.MemberOffset))
+		if !ok {
+			continue
+		}
+		if betterSarosMagicMatch(info, distance, best, bestDistance) {
+			bestDistance = distance
+			best = info
+		}
+	}
+	if bestDistance <= sarosMagicMatchLimitDay {
+		return best, true
+	}
+	return SarosInfo{}, false
+}
+
+func matchSarosMagicCandidate(ttJDE float64, anchor sarosAnchor, memberOffset int) (SarosInfo, float64, bool) {
+	headTT := basic.JDECalc(int(anchor.Year), int(anchor.Month), float64(anchor.Day))
+	if math.IsNaN(headTT) {
+		return SarosInfo{}, 0, false
+	}
+	member := int(math.Round((ttJDE-headTT)/sarosCycleDays)) + 1 + memberOffset
+	if member < 1 || member > int(anchor.Count) {
+		return SarosInfo{}, 0, false
+	}
+	expectedTT := headTT + float64(member-1-memberOffset)*sarosCycleDays
+	return SarosInfo{
+		Series: int(anchor.Series),
+		Member: member,
+		Count:  int(anchor.Count),
+	}, math.Abs(ttJDE - expectedTT), true
+}
+
+func betterSarosMagicMatch(info SarosInfo, distance float64, best SarosInfo, bestDistance float64) bool {
+	if distance < bestDistance-sarosMagicTieEpsilonDay {
+		return true
+	}
+	if math.Abs(distance-bestDistance) > sarosMagicTieEpsilonDay {
+		return false
+	}
+	if info.Series != best.Series {
+		return info.Series < best.Series
+	}
+	return info.Member < best.Member
+}
+
+func decodeSarosMagic(magic sarosMagic, series int) sarosAnchor {
+	value := uint32(magic)
+	return sarosAnchor{
+		Series: int16(series),
+		Count:  uint8((value >> sarosMagicCountShift) & sarosMagicCountMask),
+		Year:   int16(int((value>>sarosMagicYearShift)&sarosMagicYearMask) - sarosMagicYearOffset),
+		Month:  uint8((value >> sarosMagicMonthShift) & sarosMagicMonthMask),
+		Day:    uint8((value >> sarosMagicDayShift) & sarosMagicDayMask),
+	}
+}
+
+func matchSarosAnchor(anchors []sarosMagic, seriesBase int, headTT float64) (sarosAnchor, bool) {
 	headDate := basic.JDE2DateByZone(headTT, time.UTC, true)
 	year, month, day := headDate.Date()
 	monthNumber := int(month)
-	for _, anchor := range anchors {
+	for index, magic := range anchors {
+		anchor := decodeSarosMagic(magic, seriesBase+index)
 		if int(anchor.Year) == year && int(anchor.Month) == monthNumber && int(anchor.Day) == day {
 			return anchor, true
 		}

eclipse/saros_table_lunar.go

@@ -2,185 +2,185 @@ package eclipse
 
 // Code generated by /tmp/generate_saros_tables.go; DO NOT EDIT.
 
-var lunarSarosAnchors = [...]sarosAnchor{
-	{Series: 1, Count: 73, Year: -2570, Month: 3, Day: 14},
-	{Series: 2, Count: 73, Year: -2523, Month: 3, Day: 3},
-	{Series: 3, Count: 76, Year: -2567, Month: 12, Day: 30},
-	{Series: 4, Count: 78, Year: -2646, Month: 10, Day: 6},
-	{Series: 5, Count: 77, Year: -2455, Month: 12, Day: 22},
-	{Series: 6, Count: 86, Year: -2624, Month: 8, Day: 4},
-	{Series: 7, Count: 89, Year: -2595, Month: 7, Day: 16},
-	{Series: 8, Count: 86, Year: -2494, Month: 8, Day: 8},
-	{Series: 9, Count: 75, Year: -2501, Month: 6, Day: 26},
-	{Series: 10, Count: 74, Year: -2454, Month: 6, Day: 17},
-	{Series: 11, Count: 74, Year: -2371, Month: 6, Day: 29},
-	{Series: 12, Count: 73, Year: -2360, Month: 5, Day: 28},
-	{Series: 13, Count: 73, Year: -2313, Month: 5, Day: 20},
-	{Series: 14, Count: 73, Year: -2230, Month: 6, Day: 1},
-	{Series: 15, Count: 73, Year: -2219, Month: 4, Day: 30},
-	{Series: 16, Count: 73, Year: -2172, Month: 4, Day: 21},
-	{Series: 17, Count: 72, Year: -2089, Month: 5, Day: 4},
-	{Series: 18, Count: 73, Year: -2078, Month: 4, Day: 2},
-	{Series: 19, Count: 73, Year: -2031, Month: 3, Day: 24},
-	{Series: 20, Count: 72, Year: -1948, Month: 4, Day: 5},
-	{Series: 21, Count: 74, Year: -1955, Month: 2, Day: 22},
-	{Series: 22, Count: 74, Year: -1926, Month: 2, Day: 2},
-	{Series: 23, Count: 73, Year: -1825, Month: 2, Day: 25},
-	{Series: 24, Count: 85, Year: -2031, Month: 9, Day: 16},
-	{Series: 25, Count: 87, Year: -2038, Month: 8, Day: 6},
-	{Series: 26, Count: 85, Year: -1919, Month: 9, Day: 9},
-	{Series: 27, Count: 85, Year: -1926, Month: 7, Day: 28},
-	{Series: 28, Count: 74, Year: -1897, Month: 7, Day: 9},
-	{Series: 29, Count: 83, Year: -1814, Month: 7, Day: 21},
-	{Series: 30, Count: 74, Year: -1803, Month: 6, Day: 19},
-	{Series: 31, Count: 73, Year: -1774, Month: 5, Day: 30},
-	{Series: 32, Count: 73, Year: -1673, Month: 6, Day: 23},
-	{Series: 33, Count: 73, Year: -1662, Month: 5, Day: 22},
-	{Series: 34, Count: 72, Year: -1615, Month: 5, Day: 13},
-	{Series: 35, Count: 72, Year: -1532, Month: 5, Day: 25},
-	{Series: 36, Count: 73, Year: -1521, Month: 4, Day: 24},
-	{Series: 37, Count: 72, Year: -1492, Month: 4, Day: 3},
-	{Series: 38, Count: 72, Year: -1391, Month: 4, Day: 27},
-	{Series: 39, Count: 73, Year: -1380, Month: 3, Day: 26},
-	{Series: 40, Count: 73, Year: -1369, Month: 2, Day: 24},
-	{Series: 41, Count: 73, Year: -1268, Month: 3, Day: 18},
-	{Series: 42, Count: 74, Year: -1275, Month: 2, Day: 4},
-	{Series: 43, Count: 85, Year: -1463, Month: 9, Day: 7},
-	{Series: 44, Count: 76, Year: -1199, Month: 1, Day: 6},
-	{Series: 45, Count: 85, Year: -1351, Month: 8, Day: 29},
-	{Series: 46, Count: 76, Year: -1358, Month: 7, Day: 19},
-	{Series: 47, Count: 86, Year: -1275, Month: 7, Day: 31},
-	{Series: 48, Count: 75, Year: -1228, Month: 7, Day: 21},
-	{Series: 49, Count: 73, Year: -1217, Month: 6, Day: 21},
-	{Series: 50, Count: 73, Year: -1134, Month: 7, Day: 3},
-	{Series: 51, Count: 73, Year: -1105, Month: 6, Day: 13},
-	{Series: 52, Count: 72, Year: -1076, Month: 5, Day: 23},
-	{Series: 53, Count: 72, Year: -993, Month: 6, Day: 5},
-	{Series: 54, Count: 72, Year: -946, Month: 5, Day: 26},
-	{Series: 55, Count: 72, Year: -935, Month: 4, Day: 25},
-	{Series: 56, Count: 72, Year: -852, Month: 5, Day: 7},
-	{Series: 57, Count: 73, Year: -823, Month: 4, Day: 16},
-	{Series: 58, Count: 73, Year: -812, Month: 3, Day: 16},
-	{Series: 59, Count: 71, Year: -711, Month: 4, Day: 9},
-	{Series: 60, Count: 73, Year: -700, Month: 3, Day: 8},
-	{Series: 61, Count: 78, Year: -780, Month: 12, Day: 13},
-	{Series: 62, Count: 74, Year: -624, Month: 2, Day: 8},
-	{Series: 63, Count: 82, Year: -722, Month: 11, Day: 3},
-	{Series: 64, Count: 84, Year: -783, Month: 8, Day: 20},
-	{Series: 65, Count: 86, Year: -736, Month: 8, Day: 11},
-	{Series: 66, Count: 84, Year: -671, Month: 8, Day: 12},
-	{Series: 67, Count: 73, Year: -660, Month: 7, Day: 11},
-	{Series: 68, Count: 72, Year: -595, Month: 7, Day: 14},
-	{Series: 69, Count: 73, Year: -530, Month: 7, Day: 15},
-	{Series: 70, Count: 72, Year: -519, Month: 6, Day: 13},
-	{Series: 71, Count: 72, Year: -472, Month: 6, Day: 4},
-	{Series: 72, Count: 72, Year: -389, Month: 6, Day: 17},
-	{Series: 73, Count: 72, Year: -378, Month: 5, Day: 16},
-	{Series: 74, Count: 72, Year: -331, Month: 5, Day: 7},
-	{Series: 75, Count: 72, Year: -266, Month: 5, Day: 8},
-	{Series: 76, Count: 73, Year: -255, Month: 4, Day: 7},
-	{Series: 77, Count: 72, Year: -190, Month: 4, Day: 9},
-	{Series: 78, Count: 72, Year: -125, Month: 4, Day: 10},
-	{Series: 79, Count: 73, Year: -132, Month: 2, Day: 27},
-	{Series: 80, Count: 74, Year: -103, Month: 2, Day: 7},
-	{Series: 81, Count: 74, Year: -20, Month: 2, Day: 19},
-	{Series: 82, Count: 84, Year: -208, Month: 9, Day: 21},
-	{Series: 83, Count: 84, Year: -197, Month: 8, Day: 22},
-	{Series: 84, Count: 84, Year: -96, Month: 9, Day: 13},
-	{Series: 85, Count: 76, Year: -103, Month: 8, Day: 2},
-	{Series: 86, Count: 73, Year: -74, Month: 7, Day: 13},
-	{Series: 87, Count: 73, Year: 27, Month: 8, Day: 6},
-	{Series: 88, Count: 72, Year: 38, Month: 7, Day: 5},
-	{Series: 89, Count: 72, Year: 67, Month: 6, Day: 15},
-	{Series: 90, Count: 72, Year: 150, Month: 6, Day: 27},
-	{Series: 91, Count: 72, Year: 179, Month: 6, Day: 7},
-	{Series: 92, Count: 71, Year: 208, Month: 5, Day: 17},
-	{Series: 93, Count: 71, Year: 291, Month: 5, Day: 30},
-	{Series: 94, Count: 71, Year: 320, Month: 5, Day: 9},
-	{Series: 95, Count: 71, Year: 349, Month: 4, Day: 19},
-	{Series: 96, Count: 71, Year: 432, Month: 5, Day: 1},
-	{Series: 97, Count: 72, Year: 443, Month: 3, Day: 31},
-	{Series: 98, Count: 74, Year: 436, Month: 2, Day: 18},
-	{Series: 99, Count: 72, Year: 555, Month: 3, Day: 24},
-	{Series: 100, Count: 79, Year: 439, Month: 12, Day: 6},
-	{Series: 101, Count: 83, Year: 360, Month: 9, Day: 11},
-	{Series: 102, Count: 84, Year: 461, Month: 10, Day: 5},
-	{Series: 103, Count: 82, Year: 472, Month: 9, Day: 3},
-	{Series: 104, Count: 72, Year: 483, Month: 8, Day: 4},
-	{Series: 105, Count: 73, Year: 566, Month: 8, Day: 16},
-	{Series: 106, Count: 73, Year: 595, Month: 7, Day: 27},
-	{Series: 107, Count: 72, Year: 606, Month: 6, Day: 26},
-	{Series: 108, Count: 72, Year: 689, Month: 7, Day: 8},
-	{Series: 109, Count: 71, Year: 736, Month: 6, Day: 27},
-	{Series: 110, Count: 72, Year: 747, Month: 5, Day: 28},
-	{Series: 111, Count: 71, Year: 830, Month: 6, Day: 10},
-	{Series: 112, Count: 72, Year: 859, Month: 5, Day: 20},
-	{Series: 113, Count: 71, Year: 888, Month: 4, Day: 29},
-	{Series: 114, Count: 71, Year: 971, Month: 5, Day: 13},
-	{Series: 115, Count: 72, Year: 1000, Month: 4, Day: 21},
-	{Series: 116, Count: 73, Year: 993, Month: 3, Day: 11},
-	{Series: 117, Count: 71, Year: 1094, Month: 4, Day: 3},
-	{Series: 118, Count: 73, Year: 1105, Month: 3, Day: 2},
-	{Series: 119, Count: 82, Year: 935, Month: 10, Day: 14},
-	{Series: 120, Count: 83, Year: 1000, Month: 10, Day: 16},
-	{Series: 121, Count: 82, Year: 1047, Month: 10, Day: 6},
-	{Series: 122, Count: 74, Year: 1022, Month: 8, Day: 14},
-	{Series: 123, Count: 72, Year: 1087, Month: 8, Day: 16},
-	{Series: 124, Count: 73, Year: 1152, Month: 8, Day: 17},
-	{Series: 125, Count: 72, Year: 1163, Month: 7, Day: 17},
-	{Series: 126, Count: 70, Year: 1228, Month: 7, Day: 18},
-	{Series: 127, Count: 72, Year: 1275, Month: 7, Day: 9},
-	{Series: 128, Count: 71, Year: 1304, Month: 6, Day: 18},
-	{Series: 129, Count: 71, Year: 1351, Month: 6, Day: 10},
-	{Series: 130, Count: 71, Year: 1416, Month: 6, Day: 10},
-	{Series: 131, Count: 72, Year: 1427, Month: 5, Day: 10},
-	{Series: 132, Count: 71, Year: 1492, Month: 5, Day: 12},
-	{Series: 133, Count: 71, Year: 1557, Month: 5, Day: 13},
-	{Series: 134, Count: 72, Year: 1550, Month: 4, Day: 1},
-	{Series: 135, Count: 71, Year: 1615, Month: 4, Day: 13},
-	{Series: 136, Count: 72, Year: 1680, Month: 4, Day: 13},
-	{Series: 137, Count: 78, Year: 1564, Month: 12, Day: 17},
-	{Series: 138, Count: 82, Year: 1521, Month: 10, Day: 15},
-	{Series: 139, Count: 79, Year: 1658, Month: 12, Day: 9},
-	{Series: 140, Count: 77, Year: 1597, Month: 9, Day: 25},
-	{Series: 141, Count: 72, Year: 1608, Month: 8, Day: 25},
-	{Series: 142, Count: 73, Year: 1709, Month: 9, Day: 19},
-	{Series: 143, Count: 72, Year: 1720, Month: 8, Day: 18},
-	{Series: 144, Count: 71, Year: 1749, Month: 7, Day: 29},
-	{Series: 145, Count: 71, Year: 1832, Month: 8, Day: 11},
-	{Series: 146, Count: 72, Year: 1843, Month: 7, Day: 11},
-	{Series: 147, Count: 70, Year: 1890, Month: 7, Day: 2},
-	{Series: 148, Count: 70, Year: 1973, Month: 7, Day: 15},
-	{Series: 149, Count: 71, Year: 1984, Month: 6, Day: 13},
-	{Series: 150, Count: 71, Year: 2013, Month: 5, Day: 25},
-	{Series: 151, Count: 71, Year: 2096, Month: 6, Day: 6},
-	{Series: 152, Count: 72, Year: 2107, Month: 5, Day: 7},
-	{Series: 153, Count: 71, Year: 2136, Month: 4, Day: 16},
-	{Series: 154, Count: 71, Year: 2237, Month: 5, Day: 10},
-	{Series: 155, Count: 73, Year: 2212, Month: 3, Day: 18},
-	{Series: 156, Count: 81, Year: 2060, Month: 11, Day: 8},
-	{Series: 157, Count: 73, Year: 2306, Month: 3, Day: 1},
-	{Series: 158, Count: 81, Year: 2154, Month: 10, Day: 21},
-	{Series: 159, Count: 73, Year: 2147, Month: 9, Day: 9},
-	{Series: 160, Count: 72, Year: 2248, Month: 10, Day: 3},
-	{Series: 161, Count: 73, Year: 2259, Month: 9, Day: 2},
-	{Series: 162, Count: 71, Year: 2288, Month: 8, Day: 12},
-	{Series: 163, Count: 70, Year: 2371, Month: 8, Day: 27},
-	{Series: 164, Count: 71, Year: 2400, Month: 8, Day: 5},
-	{Series: 165, Count: 71, Year: 2411, Month: 7, Day: 6},
-	{Series: 166, Count: 70, Year: 2494, Month: 7, Day: 18},
-	{Series: 167, Count: 71, Year: 2541, Month: 7, Day: 9},
-	{Series: 168, Count: 71, Year: 2552, Month: 6, Day: 8},
-	{Series: 169, Count: 70, Year: 2635, Month: 6, Day: 22},
-	{Series: 170, Count: 71, Year: 2664, Month: 6, Day: 1},
-	{Series: 171, Count: 71, Year: 2675, Month: 5, Day: 1},
-	{Series: 172, Count: 70, Year: 2758, Month: 5, Day: 15},
-	{Series: 173, Count: 72, Year: 2787, Month: 4, Day: 24},
-	{Series: 174, Count: 79, Year: 2635, Month: 12, Day: 16},
-	{Series: 175, Count: 74, Year: 2791, Month: 2, Day: 11},
-	{Series: 176, Count: 79, Year: 2747, Month: 12, Day: 9},
-	{Series: 177, Count: 73, Year: 2704, Month: 10, Day: 5},
-	{Series: 178, Count: 70, Year: 2769, Month: 10, Day: 7},
-	{Series: 179, Count: 73, Year: 2816, Month: 9, Day: 27},
-	{Series: 180, Count: 71, Year: 2827, Month: 8, Day: 28},
+var lunarSarosAnchors = [...]sarosMagic{
+	0x21ae3749,
+	0x21dd31c9,
+	0x21b1cf4c,
+	0x2162a34e,
+	0x2221cb4d,
+	0x21788256,
+	0x21957859,
+	0x21fa8456,
+	0x21f36d4b,
+	0x222268ca,
+	0x22756eca,
+	0x22805e49,
+	0x22af5a49,
+	0x230260c9,
+	0x230d4f49,
+	0x233c4ac9,
+	0x238f5248,
+	0x239a4149,
+	0x23c93c49,
+	0x241c42c8,
+	0x24152b4a,
+	0x2432214a,
+	0x24972cc9,
+	0x23c99855,
+	0x23c28357,
+	0x243994d5,
+	0x24327e55,
+	0x244f74ca,
+	0x24a27ad3,
+	0x24ad69ca,
+	0x24ca5f49,
+	0x252f6bc9,
+	0x253a5b49,
+	0x256956c8,
+	0x25bc5cc8,
+	0x25c74c49,
+	0x25e441c8,
+	0x26494dc8,
+	0x26543d49,
+	0x265f2c49,
+	0x26c43949,
+	0x26bd224a,
+	0x260193d5,
+	0x2709134c,
+	0x26718ed5,
+	0x266a79cc,
+	0x26bd7fd6,
+	0x26ec7acb,
+	0x26f76ac9,
+	0x274a71c9,
+	0x276766c9,
+	0x27845bc8,
+	0x27d762c8,
+	0x28065d48,
+	0x28114cc8,
+	0x286453c8,
+	0x28814849,
+	0x288c3849,
+	0x28f144c7,
+	0x28fc3449,
+	0x28acc6ce,
+	0x2948244a,
+	0x28e6b1d2,
+	0x28a98a54,
+	0x28d885d6,
+	0x29198654,
+	0x292475c9,
+	0x29657748,
+	0x29a677c9,
+	0x29b166c8,
+	0x29e06248,
+	0x2a3368c8,
+	0x2a3e5848,
+	0x2a6d53c8,
+	0x2aae5448,
+	0x2ab943c9,
+	0x2afa44c8,
+	0x2b3b4548,
+	0x2b342dc9,
+	0x2b5123ca,
+	0x2ba429ca,
+	0x2ae89ad4,
+	0x2af38b54,
+	0x2b5896d4,
+	0x2b51814c,
+	0x2b6e76c9,
+	0x2bd38349,
+	0x2bde72c8,
+	0x2bfb67c8,
+	0x2c4e6dc8,
+	0x2c6b63c8,
+	0x2c8858c7,
+	0x2cdb5f47,
+	0x2cf854c7,
+	0x2d1549c7,
+	0x2d6850c7,
+	0x2d733fc8,
+	0x2d6c294a,
+	0x2de33c48,
+	0x2d6fc34f,
+	0x2d2095d3,
+	0x2d85a2d4,
+	0x2d9091d2,
+	0x2d9b8248,
+	0x2dee8849,
+	0x2e0b7dc9,
+	0x2e166d48,
+	0x2e697448,
+	0x2e986dc7,
+	0x2ea35e48,
+	0x2ef66547,
+	0x2f135a48,
+	0x2f304ec7,
+	0x2f8356c7,
+	0x2fa04ac8,
+	0x2f9935c9,
+	0x2ffe41c7,
+	0x30093149,
+	0x2f5fa752,
+	0x2fa0a853,
+	0x2fcfa352,
+	0x2fb6874a,
+	0x2ff78848,
+	0x303888c9,
+	0x304378c8,
+	0x30847946,
+	0x30b374c8,
+	0x30d06947,
+	0x30ff6547,
+	0x31406547,
+	0x314b5548,
+	0x318c5647,
+	0x31cd56c7,
+	0x31c640c8,
+	0x320746c7,
+	0x324846c8,
+	0x31d4c8ce,
+	0x31a9a7d2,
+	0x3232c4cf,
+	0x31f59ccd,
+	0x32008cc8,
+	0x326599c9,
+	0x32708948,
+	0x328d7ec7,
+	0x32e085c7,
+	0x32eb75c8,
+	0x331a7146,
+	0x336d77c6,
+	0x337866c7,
+	0x33955cc7,
+	0x33e86347,
+	0x33f353c8,
+	0x34104847,
+	0x34755547,
+	0x345c3949,
+	0x33c4b451,
+	0x34ba30c9,
+	0x3422aad1,
+	0x341b94c9,
+	0x3480a1c8,
+	0x348b9149,
+	0x34a88647,
+	0x34fb8dc6,
+	0x351882c7,
+	0x35237347,
+	0x35767946,
+	0x35a574c7,
+	0x35b06447,
+	0x36036b46,
+	0x362060c7,
+	0x362b50c7,
+	0x367e57c6,
+	0x369b4c48,
+	0x3603c84f,
+	0x369f25ca,
+	0x3673c4cf,
+	0x3648a2c9,
+	0x3689a3c6,
+	0x36b89dc9,
+	0x36c38e47,
 }

eclipse/saros_table_solar.go

@@ -2,186 +2,186 @@ package eclipse
 
 // Code generated by /tmp/generate_saros_tables.go; DO NOT EDIT.
 
-var solarSarosAnchors = [...]sarosAnchor{
-	{Series: 0, Count: 72, Year: -2955, Month: 5, Day: 23},
-	{Series: 1, Count: 72, Year: -2872, Month: 6, Day: 4},
-	{Series: 2, Count: 73, Year: -2861, Month: 5, Day: 4},
-	{Series: 3, Count: 72, Year: -2814, Month: 4, Day: 24},
-	{Series: 4, Count: 72, Year: -2731, Month: 5, Day: 6},
-	{Series: 5, Count: 73, Year: -2720, Month: 4, Day: 4},
-	{Series: 6, Count: 72, Year: -2673, Month: 3, Day: 27},
-	{Series: 7, Count: 72, Year: -2590, Month: 4, Day: 8},
-	{Series: 8, Count: 73, Year: -2579, Month: 3, Day: 7},
-	{Series: 9, Count: 74, Year: -2568, Month: 2, Day: 6},
-	{Series: 10, Count: 73, Year: -2467, Month: 2, Day: 28},
-	{Series: 11, Count: 76, Year: -2492, Month: 1, Day: 6},
-	{Series: 12, Count: 86, Year: -2662, Month: 8, Day: 20},
-	{Series: 13, Count: 85, Year: -2543, Month: 9, Day: 23},
-	{Series: 14, Count: 85, Year: -2550, Month: 8, Day: 11},
-	{Series: 15, Count: 75, Year: -2557, Month: 7, Day: 1},
-	{Series: 16, Count: 85, Year: -2456, Month: 7, Day: 23},
-	{Series: 17, Count: 74, Year: -2427, Month: 7, Day: 3},
-	{Series: 18, Count: 73, Year: -2416, Month: 6, Day: 2},
-	{Series: 19, Count: 73, Year: -2333, Month: 6, Day: 15},
-	{Series: 20, Count: 72, Year: -2286, Month: 6, Day: 5},
-	{Series: 21, Count: 72, Year: -2275, Month: 5, Day: 5},
-	{Series: 22, Count: 71, Year: -2174, Month: 5, Day: 28},
-	{Series: 23, Count: 72, Year: -2145, Month: 5, Day: 7},
-	{Series: 24, Count: 72, Year: -2134, Month: 4, Day: 6},
-	{Series: 25, Count: 71, Year: -2033, Month: 4, Day: 30},
-	{Series: 26, Count: 72, Year: -2004, Month: 4, Day: 8},
-	{Series: 27, Count: 72, Year: -1993, Month: 3, Day: 9},
-	{Series: 28, Count: 72, Year: -1910, Month: 3, Day: 22},
-	{Series: 29, Count: 73, Year: -1881, Month: 3, Day: 1},
-	{Series: 30, Count: 83, Year: -2051, Month: 10, Day: 12},
-	{Series: 31, Count: 74, Year: -1805, Month: 1, Day: 31},
-	{Series: 32, Count: 84, Year: -1957, Month: 9, Day: 24},
-	{Series: 33, Count: 84, Year: -1982, Month: 8, Day: 2},
-	{Series: 34, Count: 86, Year: -1917, Month: 8, Day: 4},
-	{Series: 35, Count: 84, Year: -1870, Month: 7, Day: 25},
-	{Series: 36, Count: 73, Year: -1859, Month: 6, Day: 23},
-	{Series: 37, Count: 73, Year: -1794, Month: 6, Day: 25},
-	{Series: 38, Count: 73, Year: -1729, Month: 6, Day: 26},
-	{Series: 39, Count: 72, Year: -1718, Month: 5, Day: 26},
-	{Series: 40, Count: 72, Year: -1653, Month: 5, Day: 28},
-	{Series: 41, Count: 72, Year: -1588, Month: 5, Day: 28},
-	{Series: 42, Count: 72, Year: -1577, Month: 4, Day: 28},
-	{Series: 43, Count: 72, Year: -1512, Month: 4, Day: 29},
-	{Series: 44, Count: 72, Year: -1447, Month: 4, Day: 30},
-	{Series: 45, Count: 72, Year: -1436, Month: 3, Day: 30},
-	{Series: 46, Count: 72, Year: -1371, Month: 4, Day: 1},
-	{Series: 47, Count: 72, Year: -1306, Month: 4, Day: 2},
-	{Series: 48, Count: 74, Year: -1331, Month: 2, Day: 8},
-	{Series: 49, Count: 72, Year: -1248, Month: 2, Day: 22},
-	{Series: 50, Count: 73, Year: -1201, Month: 2, Day: 11},
-	{Series: 51, Count: 85, Year: -1407, Month: 9, Day: 2},
-	{Series: 52, Count: 86, Year: -1378, Month: 8, Day: 14},
-	{Series: 53, Count: 84, Year: -1277, Month: 9, Day: 6},
-	{Series: 54, Count: 74, Year: -1284, Month: 7, Day: 25},
-	{Series: 55, Count: 73, Year: -1255, Month: 7, Day: 6},
-	{Series: 56, Count: 74, Year: -1172, Month: 7, Day: 17},
-	{Series: 57, Count: 73, Year: -1161, Month: 6, Day: 17},
-	{Series: 58, Count: 72, Year: -1114, Month: 6, Day: 7},
-	{Series: 59, Count: 72, Year: -1031, Month: 6, Day: 19},
-	{Series: 60, Count: 72, Year: -1020, Month: 5, Day: 18},
-	{Series: 61, Count: 71, Year: -973, Month: 5, Day: 10},
-	{Series: 62, Count: 71, Year: -890, Month: 5, Day: 22},
-	{Series: 63, Count: 72, Year: -879, Month: 4, Day: 20},
-	{Series: 64, Count: 71, Year: -832, Month: 4, Day: 11},
-	{Series: 65, Count: 71, Year: -749, Month: 4, Day: 24},
-	{Series: 66, Count: 73, Year: -756, Month: 3, Day: 12},
-	{Series: 67, Count: 72, Year: -709, Month: 3, Day: 4},
-	{Series: 68, Count: 72, Year: -626, Month: 3, Day: 16},
-	{Series: 69, Count: 78, Year: -724, Month: 12, Day: 9},
-	{Series: 70, Count: 84, Year: -821, Month: 9, Day: 5},
-	{Series: 71, Count: 82, Year: -684, Month: 10, Day: 19},
-	{Series: 72, Count: 83, Year: -727, Month: 8, Day: 16},
-	{Series: 73, Count: 72, Year: -698, Month: 7, Day: 27},
-	{Series: 74, Count: 75, Year: -615, Month: 8, Day: 8},
-	{Series: 75, Count: 73, Year: -604, Month: 7, Day: 7},
-	{Series: 76, Count: 72, Year: -575, Month: 6, Day: 18},
-	{Series: 77, Count: 71, Year: -474, Month: 7, Day: 11},
-	{Series: 78, Count: 72, Year: -463, Month: 6, Day: 9},
-	{Series: 79, Count: 71, Year: -434, Month: 5, Day: 21},
-	{Series: 80, Count: 71, Year: -333, Month: 6, Day: 13},
-	{Series: 81, Count: 72, Year: -322, Month: 5, Day: 12},
-	{Series: 82, Count: 71, Year: -293, Month: 4, Day: 22},
-	{Series: 83, Count: 71, Year: -210, Month: 5, Day: 5},
-	{Series: 84, Count: 72, Year: -181, Month: 4, Day: 14},
-	{Series: 85, Count: 72, Year: -170, Month: 3, Day: 14},
-	{Series: 86, Count: 71, Year: -69, Month: 4, Day: 6},
-	{Series: 87, Count: 73, Year: -76, Month: 2, Day: 23},
-	{Series: 88, Count: 83, Year: -246, Month: 10, Day: 6},
-	{Series: 89, Count: 73, Year: 18, Month: 2, Day: 4},
-	{Series: 90, Count: 83, Year: -134, Month: 9, Day: 28},
-	{Series: 91, Count: 75, Year: -159, Month: 8, Day: 6},
-	{Series: 92, Count: 74, Year: -76, Month: 8, Day: 19},
-	{Series: 93, Count: 74, Year: -29, Month: 8, Day: 9},
-	{Series: 94, Count: 72, Year: -18, Month: 7, Day: 9},
-	{Series: 95, Count: 71, Year: 47, Month: 7, Day: 11},
-	{Series: 96, Count: 72, Year: 94, Month: 7, Day: 1},
-	{Series: 97, Count: 71, Year: 123, Month: 6, Day: 11},
-	{Series: 98, Count: 71, Year: 188, Month: 6, Day: 12},
-	{Series: 99, Count: 72, Year: 235, Month: 6, Day: 3},
-	{Series: 100, Count: 71, Year: 264, Month: 5, Day: 13},
-	{Series: 101, Count: 71, Year: 329, Month: 5, Day: 15},
-	{Series: 102, Count: 71, Year: 376, Month: 5, Day: 5},
-	{Series: 103, Count: 72, Year: 387, Month: 4, Day: 4},
-	{Series: 104, Count: 70, Year: 470, Month: 4, Day: 17},
-	{Series: 105, Count: 72, Year: 499, Month: 3, Day: 27},
-	{Series: 106, Count: 75, Year: 456, Month: 1, Day: 23},
-	{Series: 107, Count: 72, Year: 557, Month: 2, Day: 15},
-	{Series: 108, Count: 76, Year: 550, Month: 1, Day: 4},
-	{Series: 109, Count: 81, Year: 416, Month: 9, Day: 7},
-	{Series: 110, Count: 72, Year: 463, Month: 8, Day: 30},
-	{Series: 111, Count: 79, Year: 528, Month: 8, Day: 30},
-	{Series: 112, Count: 72, Year: 539, Month: 7, Day: 31},
-	{Series: 113, Count: 71, Year: 586, Month: 7, Day: 22},
-	{Series: 114, Count: 72, Year: 651, Month: 7, Day: 23},
-	{Series: 115, Count: 72, Year: 662, Month: 6, Day: 21},
-	{Series: 116, Count: 70, Year: 727, Month: 6, Day: 23},
-	{Series: 117, Count: 71, Year: 792, Month: 6, Day: 24},
-	{Series: 118, Count: 72, Year: 803, Month: 5, Day: 24},
-	{Series: 119, Count: 71, Year: 850, Month: 5, Day: 15},
-	{Series: 120, Count: 71, Year: 933, Month: 5, Day: 27},
-	{Series: 121, Count: 71, Year: 944, Month: 4, Day: 25},
-	{Series: 122, Count: 70, Year: 991, Month: 4, Day: 17},
-	{Series: 123, Count: 70, Year: 1074, Month: 4, Day: 29},
-	{Series: 124, Count: 73, Year: 1049, Month: 3, Day: 6},
-	{Series: 125, Count: 73, Year: 1060, Month: 2, Day: 4},
-	{Series: 126, Count: 72, Year: 1179, Month: 3, Day: 10},
-	{Series: 127, Count: 82, Year: 991, Month: 10, Day: 10},
-	{Series: 128, Count: 73, Year: 984, Month: 8, Day: 29},
-	{Series: 129, Count: 80, Year: 1103, Month: 10, Day: 3},
-	{Series: 130, Count: 73, Year: 1096, Month: 8, Day: 20},
-	{Series: 131, Count: 70, Year: 1125, Month: 8, Day: 1},
-	{Series: 132, Count: 71, Year: 1208, Month: 8, Day: 13},
-	{Series: 133, Count: 72, Year: 1219, Month: 7, Day: 13},
-	{Series: 134, Count: 71, Year: 1248, Month: 6, Day: 22},
-	{Series: 135, Count: 71, Year: 1331, Month: 7, Day: 5},
-	{Series: 136, Count: 71, Year: 1360, Month: 6, Day: 14},
-	{Series: 137, Count: 70, Year: 1389, Month: 5, Day: 25},
-	{Series: 138, Count: 70, Year: 1472, Month: 6, Day: 6},
-	{Series: 139, Count: 71, Year: 1501, Month: 5, Day: 17},
-	{Series: 140, Count: 71, Year: 1512, Month: 4, Day: 16},
-	{Series: 141, Count: 70, Year: 1613, Month: 5, Day: 19},
-	{Series: 142, Count: 72, Year: 1624, Month: 4, Day: 17},
-	{Series: 143, Count: 72, Year: 1617, Month: 3, Day: 7},
-	{Series: 144, Count: 70, Year: 1736, Month: 4, Day: 11},
-	{Series: 145, Count: 77, Year: 1639, Month: 1, Day: 4},
-	{Series: 146, Count: 76, Year: 1541, Month: 9, Day: 19},
-	{Series: 147, Count: 80, Year: 1624, Month: 10, Day: 12},
-	{Series: 148, Count: 75, Year: 1653, Month: 9, Day: 21},
-	{Series: 149, Count: 71, Year: 1664, Month: 8, Day: 21},
-	{Series: 150, Count: 71, Year: 1729, Month: 8, Day: 24},
-	{Series: 151, Count: 72, Year: 1776, Month: 8, Day: 14},
-	{Series: 152, Count: 70, Year: 1805, Month: 7, Day: 26},
-	{Series: 153, Count: 70, Year: 1870, Month: 7, Day: 28},
-	{Series: 154, Count: 71, Year: 1917, Month: 7, Day: 19},
-	{Series: 155, Count: 71, Year: 1928, Month: 6, Day: 17},
-	{Series: 156, Count: 69, Year: 2011, Month: 7, Day: 1},
-	{Series: 157, Count: 70, Year: 2058, Month: 6, Day: 21},
-	{Series: 158, Count: 70, Year: 2069, Month: 5, Day: 20},
-	{Series: 159, Count: 70, Year: 2134, Month: 5, Day: 23},
-	{Series: 160, Count: 71, Year: 2181, Month: 5, Day: 13},
-	{Series: 161, Count: 72, Year: 2174, Month: 4, Day: 1},
-	{Series: 162, Count: 70, Year: 2257, Month: 4, Day: 15},
-	{Series: 163, Count: 72, Year: 2286, Month: 3, Day: 25},
-	{Series: 164, Count: 80, Year: 2098, Month: 10, Day: 24},
-	{Series: 165, Count: 72, Year: 2145, Month: 10, Day: 16},
-	{Series: 166, Count: 77, Year: 2228, Month: 10, Day: 29},
-	{Series: 167, Count: 72, Year: 2203, Month: 9, Day: 6},
-	{Series: 168, Count: 70, Year: 2250, Month: 8, Day: 28},
-	{Series: 169, Count: 71, Year: 2333, Month: 9, Day: 10},
-	{Series: 170, Count: 71, Year: 2344, Month: 8, Day: 9},
-	{Series: 171, Count: 69, Year: 2391, Month: 8, Day: 1},
-	{Series: 172, Count: 70, Year: 2474, Month: 8, Day: 13},
-	{Series: 173, Count: 70, Year: 2485, Month: 7, Day: 12},
-	{Series: 174, Count: 69, Year: 2532, Month: 7, Day: 4},
-	{Series: 175, Count: 70, Year: 2597, Month: 7, Day: 5},
-	{Series: 176, Count: 71, Year: 2608, Month: 6, Day: 4},
-	{Series: 177, Count: 69, Year: 2655, Month: 5, Day: 27},
-	{Series: 178, Count: 70, Year: 2738, Month: 6, Day: 9},
-	{Series: 179, Count: 71, Year: 2731, Month: 4, Day: 28},
-	{Series: 180, Count: 70, Year: 2760, Month: 4, Day: 8},
+var solarSarosAnchors = [...]sarosMagic{
+	0x202d5bc8,
+	0x20806248,
+	0x208b5249,
+	0x20ba4c48,
+	0x210d5348,
+	0x21184249,
+	0x21473dc8,
+	0x219a4448,
+	0x21a533c9,
+	0x21b0234a,
+	0x22152e49,
+	0x21fc134c,
+	0x21528a56,
+	0x21c99bd5,
+	0x21c285d5,
+	0x21bb70cb,
+	0x22207bd5,
+	0x223d71ca,
+	0x22486149,
+	0x229b67c9,
+	0x22ca62c8,
+	0x22d552c8,
+	0x233a5e47,
+	0x235753c8,
+	0x23624348,
+	0x23c74f47,
+	0x23e44448,
+	0x23ef34c8,
+	0x24423b48,
+	0x245f30c9,
+	0x23b5a653,
+	0x24ab1fca,
+	0x24139c54,
+	0x23fa8154,
+	0x243b8256,
+	0x246a7cd4,
+	0x24756bc9,
+	0x24b66cc9,
+	0x24f76d49,
+	0x25025d48,
+	0x25435e48,
+	0x25845e48,
+	0x258f4e48,
+	0x25d04ec8,
+	0x26114f48,
+	0x261c3f48,
+	0x265d40c8,
+	0x269e4148,
+	0x2685244a,
+	0x26d82b48,
+	0x270725c9,
+	0x26399155,
+	0x26568756,
+	0x26bb9354,
+	0x26b47cca,
+	0x26d17349,
+	0x272478ca,
+	0x272f68c9,
+	0x275e63c8,
+	0x27b169c8,
+	0x27bc5948,
+	0x27eb5547,
+	0x283e5b47,
+	0x28494a48,
+	0x287845c7,
+	0x28cb4c47,
+	0x28c43649,
+	0x28f33248,
+	0x29463848,
+	0x28e4c4ce,
+	0x288392d4,
+	0x290ca9d2,
+	0x28e18853,
+	0x28fe7dc8,
+	0x2951844b,
+	0x295c73c9,
+	0x29796948,
+	0x29de75c7,
+	0x29e964c8,
+	0x2a065ac7,
+	0x2a6b66c7,
+	0x2a765648,
+	0x2a934b47,
+	0x2ae652c7,
+	0x2b034748,
+	0x2b0e3748,
+	0x2b734347,
+	0x2b6c2bc9,
+	0x2ac2a353,
+	0x2bca2249,
+	0x2b329e53,
+	0x2b19834b,
+	0x2b6c89ca,
+	0x2b9b84ca,
+	0x2ba674c8,
+	0x2be775c7,
+	0x2c1670c8,
+	0x2c3365c7,
+	0x2c746647,
+	0x2ca361c8,
+	0x2cc056c7,
+	0x2d0157c7,
+	0x2d3052c7,
+	0x2d3b4248,
+	0x2d8e48c6,
+	0x2dab3dc8,
+	0x2d801bcb,
+	0x2de527c8,
+	0x2dde124c,
+	0x2d5893d1,
+	0x2d878f48,
+	0x2dc88f4f,
+	0x2dd37fc8,
+	0x2e027b47,
+	0x2e437bc8,
+	0x2e4e6ac8,
+	0x2e8f6bc6,
+	0x2ed06c47,
+	0x2edb5c48,
+	0x2f0a57c7,
+	0x2f5d5dc7,
+	0x2f684cc7,
+	0x2f9748c6,
+	0x2fea4ec6,
+	0x2fd13349,
+	0x2fdc2249,
+	0x30533548,
+	0x2f97a552,
+	0x2f908ec9,
+	0x3007a1d0,
+	0x30008a49,
+	0x301d80c6,
+	0x307086c7,
+	0x307b76c8,
+	0x30986b47,
+	0x30eb72c7,
+	0x31086747,
+	0x31255cc6,
+	0x31786346,
+	0x319558c7,
+	0x31a04847,
+	0x320559c6,
+	0x321048c8,
+	0x320933c8,
+	0x328045c6,
+	0x321f124d,
+	0x31bd99cc,
+	0x3210a650,
+	0x322d9acb,
+	0x32388ac7,
+	0x32798c47,
+	0x32a88748,
+	0x32c57d46,
+	0x33067e46,
+	0x333579c7,
+	0x334068c7,
+	0x339370c5,
+	0x33c26ac6,
+	0x33cd5a46,
+	0x340e5bc6,
+	0x343d56c7,
+	0x343640c8,
+	0x348947c6,
+	0x34a63cc8,
+	0x33eaac50,
+	0x3419a848,
+	0x346caecd,
+	0x34539348,
+	0x34828e46,
+	0x34d59547,
+	0x34e084c7,
+	0x350f80c5,
+	0x356286c6,
+	0x356d7646,
+	0x359c7245,
+	0x35dd72c6,
+	0x35e86247,
+	0x36175dc5,
+	0x366a64c6,
+	0x36634e47,
+	0x36804446,
 }

eclipse/saros_test.go

@@ -117,10 +117,10 @@ func TestSolarPathAndFootprintsCarrySaros(t *testing.T) {
 }
 
 func TestSarosAnchorSanity(t *testing.T) {
-	assertSarosAnchorTable(t, solarSarosAnchors[:], true)
-	assertSarosAnchorTable(t, lunarSarosAnchors[:], false)
-	assertSarosHeadOverrides(t, solarSarosHeadOverrides[:], solarSarosAnchors[:])
-	assertSarosHeadOverrides(t, lunarSarosHeadOverrides[:], lunarSarosAnchors[:])
+	assertSarosAnchorTable(t, solarSarosAnchors[:], 0)
+	assertSarosAnchorTable(t, lunarSarosAnchors[:], 1)
+	assertSarosHeadOverrides(t, solarSarosHeadOverrides[:], solarSarosAnchors[:], 0)
+	assertSarosHeadOverrides(t, lunarSarosHeadOverrides[:], lunarSarosAnchors[:], 1)
 }
 
 func assertSarosInfo(t *testing.T, has bool, got SarosInfo, wantSeries, wantMember, wantCount int) {
@@ -141,14 +141,15 @@ func assertSarosInfo(t *testing.T, has bool, got SarosInfo, wantSeries, wantMemb
 	}
 }
 
-func assertSarosAnchorTable(t *testing.T, anchors []sarosAnchor, solar bool) {
+func assertSarosAnchorTable(t *testing.T, anchors []sarosMagic, seriesBase int) {
 	t.Helper()
 	if len(anchors) == 0 {
 		t.Fatal("expected non-empty Saros anchor table")
 	}
 	seenDates := make(map[[3]int]int, len(anchors))
-	lastSeries := int(anchors[0].Series) - 1
-	for _, anchor := range anchors {
+	lastSeries := seriesBase - 1
+	for index, magic := range anchors {
+		anchor := decodeSarosMagic(magic, seriesBase+index)
 		series := int(anchor.Series)
 		if series <= lastSeries {
 			t.Fatalf("series not strictly increasing: prev=%d current=%d", lastSeries, series)
@@ -163,25 +164,20 @@ func assertSarosAnchorTable(t *testing.T, anchors []sarosAnchor, solar bool) {
 		}
 		seenDates[dateKey] = series
 	}
-	if solar {
-		if got := int(anchors[0].Series); got != 0 {
-			t.Fatalf("unexpected first solar series: got %d want 0", got)
-		}
-	} else {
-		if got := int(anchors[0].Series); got != 1 {
-			t.Fatalf("unexpected first lunar series: got %d want 1", got)
-		}
+	if got := int(decodeSarosMagic(anchors[0], seriesBase).Series); got != seriesBase {
+		t.Fatalf("unexpected first series: got %d want %d", got, seriesBase)
 	}
 }
 
-func assertSarosHeadOverrides(t *testing.T, overrides []sarosHeadOverride, anchors []sarosAnchor) {
+func assertSarosHeadOverrides(t *testing.T, overrides []sarosHeadOverride, anchors []sarosMagic, seriesBase int) {
 	t.Helper()
 	if len(overrides) == 0 {
 		return
 	}
 	seenHeads := make(map[[3]int]int, len(overrides))
 	anchorSeries := make(map[int]int, len(anchors))
-	for _, anchor := range anchors {
+	for index, magic := range anchors {
+		anchor := decodeSarosMagic(magic, seriesBase+index)
 		anchorSeries[int(anchor.Series)] = int(anchor.Count)
 	}
 	for _, override := range overrides {

eclipse/search_skip.go

@@ -0,0 +1,36 @@
+package eclipse
+
+import (
+	"math"
+
+	"b612.me/astro/basic"
+)
+
+const (
+	eclipseSeasonNodeDistanceLimitDeg = 35.0
+	eclipseSeasonMaxSearchStep        = 4
+)
+
+func nextEclipseSearchCandidateTT(candidateTT float64, phaseType, direction int, synodicMonthDays float64) float64 {
+	step := eclipseSearchStep(candidateTT, direction, synodicMonthDays)
+	return basic.CalcMoonSHByJDE(candidateTT+float64(direction*step)*synodicMonthDays, phaseType)
+}
+
+func eclipseSearchStep(candidateTT float64, direction int, synodicMonthDays float64) int {
+	step := 1
+	for nextStep := 2; nextStep <= eclipseSeasonMaxSearchStep; nextStep++ {
+		skippedTT := candidateTT + float64(direction*(nextStep-1))*synodicMonthDays
+		if eclipseNodeDistance(skippedTT) < eclipseSeasonNodeDistanceLimitDeg {
+			break
+		}
+		step = nextStep
+	}
+	return step
+}
+
+func eclipseNodeDistance(ttJDE float64) float64 {
+	argument := normalizeDegree360(basic.MoonLonX(ttJDE))
+	toAscending := math.Min(argument, 360-argument)
+	toDescending := math.Abs(argument - 180)
+	return math.Min(toAscending, toDescending)
+}

eclipse/search_skip_test.go

@@ -0,0 +1,73 @@
+package eclipse
+
+import (
+	"testing"
+	"time"
+
+	"b612.me/astro/basic"
+)
+
+func TestEclipseSearchStepDoesNotSkipPotentialCandidates(t *testing.T) {
+	testCases := []struct {
+		name             string
+		phaseType        int
+		synodicMonthDays float64
+		potential        func(float64) bool
+	}{
+		{
+			name:             "solar",
+			phaseType:        0,
+			synodicMonthDays: solarEclipseSynodicMonthDays,
+			potential:        isPotentialSolarEclipse,
+		},
+		{
+			name:             "lunar",
+			phaseType:        1,
+			synodicMonthDays: lunarEclipseSynodicMonthDays,
+			potential:        isPotentialLunarEclipse,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			candidates := eclipseSearchTestCandidates(1600, 800, tc.phaseType, tc.synodicMonthDays)
+
+			for index, candidateTT := range candidates {
+				for _, direction := range []int{-1, 1} {
+					step := eclipseSearchStep(candidateTT, direction, tc.synodicMonthDays)
+					for offset := 1; offset < step; offset++ {
+						skippedIndex := index + direction*offset
+						if skippedIndex < 0 || skippedIndex >= len(candidates) {
+							continue
+						}
+						if tc.potential(candidates[skippedIndex]) {
+							t.Fatalf(
+								"%s skip crosses potential candidate: index=%d direction=%d step=%d offset=%d jd=%.8f",
+								tc.name,
+								index,
+								direction,
+								step,
+								offset,
+								candidates[skippedIndex],
+							)
+						}
+					}
+				}
+			}
+		})
+	}
+}
+
+func eclipseSearchTestCandidates(startYear, years, phaseType int, synodicMonthDays float64) []float64 {
+	startTT := basic.Date2JDE(time.Date(startYear, 1, 1, 0, 0, 0, 0, time.UTC))
+	endTT := basic.Date2JDE(time.Date(startYear+years, 1, 1, 0, 0, 0, 0, time.UTC))
+	candidateTT := basic.CalcMoonSHByJDE(startTT, phaseType)
+	candidates := make([]float64, 0, years*13)
+	for candidateTT < endTT {
+		if candidateTT >= startTT {
+			candidates = append(candidates, candidateTT)
+		}
+		candidateTT = basic.CalcMoonSHByJDE(candidateTT+synodicMonthDays, phaseType)
+	}
+	return candidates
+}

eclipse/solar.go

@@ -11,6 +11,7 @@ const (
 	solarEclipseSynodicMonthDays = 29.530588853
 	solarEclipseSearchLimit      = 36
 	solarEclipseSearchEpsilonDay = 1e-8
+	solarEclipseLatitudeLimitDeg = 2.0
 )
 
 type solarEclipseCalculator func(float64) basic.SolarEclipseResult
@@ -236,16 +237,22 @@ func searchSolarEclipse(
 	candidateTT := basic.CalcMoonSHByJDE(targetTT, 0)
 
 	for i := 0; i < solarEclipseSearchLimit; i++ {
+		if isPotentialSolarEclipse(candidateTT) {
 			result := calculator(candidateTT)
 			if result.Type != basic.SolarEclipseNone && solarEclipseMatchesDirection(result.GreatestEclipse, targetTT, direction, includeCurrent) {
 				return solarEclipseInfoFromBasic(result, date.Location()), true
 			}
-		candidateTT = basic.CalcMoonSHByJDE(candidateTT+float64(direction)*solarEclipseSynodicMonthDays, 0)
+		}
+		candidateTT = nextEclipseSearchCandidateTT(candidateTT, 0, direction, solarEclipseSynodicMonthDays)
 	}
 
 	return SolarEclipseInfo{}, false
 }
 
+func isPotentialSolarEclipse(newMoonTT float64) bool {
+	return math.Abs(basic.HMoonTrueBo(newMoonTT)) <= solarEclipseLatitudeLimitDeg
+}
+
 func solarEclipseMatchesDirection(greatestTT, targetTT float64, direction int, includeCurrent bool) bool {
 	delta := greatestTT - targetTT
 	if math.Abs(delta) <= solarEclipseSearchEpsilonDay {

eclipse/solar_local.go

@@ -217,6 +217,18 @@ func LastGeometricLocalSolarEclipseIAUSingleK(date time.Time, lon, lat, height f
 	return info
 }
 
+// LastLocalTotalSolarEclipse 上次站心日全食 / previous local total solar eclipse.
+// Previous visible local total solar eclipse, using NASA bulletin Split-K by default.
+func LastLocalTotalSolarEclipse(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
+	return searchLocalTotalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
+}
+
+// LastLocalAnnularSolarEclipse 上次站心日环食 / previous local annular solar eclipse.
+// Previous visible local annular solar eclipse, using NASA bulletin Split-K by default.
+func LastLocalAnnularSolarEclipse(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
+	return searchLocalAnnularSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
+}
+
 // NextLocalSolarEclipse 下次站心日食 / next local solar eclipse.
 // Next visible local solar eclipse, using NASA bulletin Split-K by default.
 func NextLocalSolarEclipse(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
@@ -257,6 +269,18 @@ func NextGeometricLocalSolarEclipseIAUSingleK(date time.Time, lon, lat, height f
 	return info
 }
 
+// NextLocalTotalSolarEclipse 下次站心日全食 / next local total solar eclipse.
+// Next visible local total solar eclipse, using NASA bulletin Split-K by default.
+func NextLocalTotalSolarEclipse(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
+	return searchLocalTotalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
+}
+
+// NextLocalAnnularSolarEclipse 下次站心日环食 / next local annular solar eclipse.
+// Next visible local annular solar eclipse, using NASA bulletin Split-K by default.
+func NextLocalAnnularSolarEclipse(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
+	return searchLocalAnnularSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
+}
+
 // ClosestLocalSolarEclipse 最近一次站心日食 / closest local solar eclipse.
 // Closest visible local solar eclipse, using NASA bulletin Split-K by default.
 func ClosestLocalSolarEclipse(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
@@ -301,6 +325,22 @@ func ClosestGeometricLocalSolarEclipseIAUSingleK(date time.Time, lon, lat, heigh
 	return closestLocalSolarEclipse(date, last, hasLast, next, hasNext)
 }
 
+// ClosestLocalTotalSolarEclipse 最近一次站心日全食 / closest local total solar eclipse.
+// Closest visible local total solar eclipse, using NASA bulletin Split-K by default.
+func ClosestLocalTotalSolarEclipse(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
+	last, hasLast := searchLocalTotalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
+	next, hasNext := searchLocalTotalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
+	return closestLocalSolarEclipseResult(date, last, hasLast, next, hasNext)
+}
+
+// ClosestLocalAnnularSolarEclipse 最近一次站心日环食 / closest local annular solar eclipse.
+// Closest visible local annular solar eclipse, using NASA bulletin Split-K by default.
+func ClosestLocalAnnularSolarEclipse(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
+	last, hasLast := searchLocalAnnularSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
+	next, hasNext := searchLocalAnnularSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
+	return closestLocalSolarEclipseResult(date, last, hasLast, next, hasNext)
+}
+
 func closestLocalSolarEclipse(
 	date time.Time,
 	last LocalSolarEclipseInfo,
@@ -308,21 +348,32 @@ func closestLocalSolarEclipse(
 	next LocalSolarEclipseInfo,
 	hasNext bool,
 ) LocalSolarEclipseInfo {
+	info, _ := closestLocalSolarEclipseResult(date, last, hasLast, next, hasNext)
+	return info
+}
+
+func closestLocalSolarEclipseResult(
+	date time.Time,
+	last LocalSolarEclipseInfo,
+	hasLast bool,
+	next LocalSolarEclipseInfo,
+	hasNext bool,
+) (LocalSolarEclipseInfo, bool) {
 	switch {
 	case hasLast && !hasNext:
-		return last
+		return last, true
 	case !hasLast && hasNext:
-		return next
+		return next, true
 	case !hasLast && !hasNext:
-		return LocalSolarEclipseInfo{}
+		return LocalSolarEclipseInfo{}, false
 	}
 
 	lastDistance := math.Abs(date.Sub(last.GreatestEclipse).Seconds())
 	nextDistance := math.Abs(next.GreatestEclipse.Sub(date).Seconds())
 	if lastDistance <= nextDistance {
-		return last
+		return last, true
 	}
-	return next
+	return next, true
 }
 
 func searchLocalSolarEclipse(
@@ -350,7 +401,69 @@ func searchLocalSolarEclipse(
 				}
 			}
 		}
-		candidateTT = basic.CalcMoonSHByJDE(candidateTT+float64(direction)*localSolarEclipseSynodicMonthDays, 0)
+		candidateTT = nextEclipseSearchCandidateTT(candidateTT, 0, direction, localSolarEclipseSynodicMonthDays)
+	}
+
+	return LocalSolarEclipseInfo{}, false
+}
+
+func searchLocalTotalSolarEclipse(
+	date time.Time,
+	lon, lat, height float64,
+	direction int,
+	includeCurrent bool,
+	calculator localSolarEclipseCalculator,
+	mode localSolarEclipseQueryMode,
+) (LocalSolarEclipseInfo, bool) {
+	targetTT := solarEclipseTimeToTTJDE(date)
+	candidateTT := basic.CalcMoonSHByJDE(targetTT, 0)
+
+	for i := 0; i < localSolarEclipseSearchLimit; i++ {
+		if isPotentialLocalSolarEclipse(candidateTT) {
+			globalResult := calculator.global(candidateTT)
+			if globalResult.HasTotal || globalResult.HasHybrid {
+				result := calculator.local(globalResult.GreatestEclipse, lon, lat, height)
+				if result.HasTotal {
+					info := localSolarEclipseInfoFromBasic(result, lon, lat, height, date.Location())
+					if (mode != localSolarEclipseQueryVisible || localCentralSolarEclipseVisible(info)) &&
+						localSolarEclipseMatchesDirection(result.GreatestEclipse, targetTT, direction, includeCurrent) {
+						return info, true
+					}
+				}
+			}
+		}
+		candidateTT = nextEclipseSearchCandidateTT(candidateTT, 0, direction, localSolarEclipseSynodicMonthDays)
+	}
+
+	return LocalSolarEclipseInfo{}, false
+}
+
+func searchLocalAnnularSolarEclipse(
+	date time.Time,
+	lon, lat, height float64,
+	direction int,
+	includeCurrent bool,
+	calculator localSolarEclipseCalculator,
+	mode localSolarEclipseQueryMode,
+) (LocalSolarEclipseInfo, bool) {
+	targetTT := solarEclipseTimeToTTJDE(date)
+	candidateTT := basic.CalcMoonSHByJDE(targetTT, 0)
+
+	for i := 0; i < localSolarEclipseSearchLimit; i++ {
+		if isPotentialLocalSolarEclipse(candidateTT) {
+			globalResult := calculator.global(candidateTT)
+			if globalResult.HasAnnular || globalResult.HasHybrid {
+				result := calculator.local(globalResult.GreatestEclipse, lon, lat, height)
+				if result.HasAnnular && !result.HasTotal {
+					info := localSolarEclipseInfoFromBasic(result, lon, lat, height, date.Location())
+					if (mode != localSolarEclipseQueryVisible || localCentralSolarEclipseVisible(info)) &&
+						localSolarEclipseMatchesDirection(result.GreatestEclipse, targetTT, direction, includeCurrent) {
+						return info, true
+					}
+				}
+			}
+		}
+		candidateTT = nextEclipseSearchCandidateTT(candidateTT, 0, direction, localSolarEclipseSynodicMonthDays)
 	}
 
 	return LocalSolarEclipseInfo{}, false
@@ -501,6 +614,13 @@ func localSolarEclipseVisible(info LocalSolarEclipseInfo) bool {
 	return localSolarEclipseVisibleDuring(info, eventStart, eventEnd)
 }
 
+func localCentralSolarEclipseVisible(info LocalSolarEclipseInfo) bool {
+	if !info.HasCentral || info.CentralStart.IsZero() || info.CentralEnd.IsZero() {
+		return false
+	}
+	return localSolarEclipseVisibleDuring(info, info.CentralStart, info.CentralEnd)
+}
+
 func localSolarEclipseVisibleOnDate(info LocalSolarEclipseInfo, dayStart, dayEnd time.Time) bool {
 	eventStart, eventEnd, ok := localSolarEclipseRange(info)
 	if !ok {

eclipse/solar_local_test.go

@@ -129,6 +129,116 @@ func TestLocalSolarEclipseSearchSkipsInvisibleCurrentCandidate(t *testing.T) {
 	}
 }
 
+func TestLocalTotalSolarEclipseSearch(t *testing.T) {
+	loc := time.UTC
+	lon, lat, height := -104.1, 25.3, 0.0
+	date := time.Date(2024, 4, 7, 0, 0, 0, 0, loc)
+
+	next, ok := NextLocalTotalSolarEclipse(date, lon, lat, height)
+	if !ok {
+		t.Fatal("expected to find next local total solar eclipse")
+	}
+	if next.Type != SolarEclipseTotal || !next.HasTotal {
+		t.Fatalf("unexpected next total eclipse: %+v", next)
+	}
+	assertSolarTimeClose(t, "NextLocalTotalSolarEclipse", next.GreatestEclipse, time.Date(2024, 4, 8, 18, 17, 15, 0, loc), time.Minute)
+	assertSolarDurationClose(t, "NextLocalTotalSolarEclipse duration", next.CentralEnd.Sub(next.CentralStart), 4*time.Minute+28*time.Second, 5*time.Second)
+
+	last, ok := LastLocalTotalSolarEclipse(next.GreatestEclipse, lon, lat, height)
+	if !ok {
+		t.Fatal("expected to find previous local total solar eclipse")
+	}
+	if last.Type != SolarEclipseTotal || !last.HasTotal {
+		t.Fatalf("unexpected last total eclipse: %+v", last)
+	}
+	assertSolarTimeClose(t, "LastLocalTotalSolarEclipse", last.GreatestEclipse, next.GreatestEclipse, time.Second)
+	assertSolarDurationClose(t, "LastLocalTotalSolarEclipse duration", last.CentralEnd.Sub(last.CentralStart), 4*time.Minute+28*time.Second, 5*time.Second)
+}
+
+func TestLocalTotalSolarEclipseClosest(t *testing.T) {
+	loc := time.UTC
+	lon, lat, height := -104.1, 25.3, 0.0
+	date := time.Date(2024, 4, 8, 12, 0, 0, 0, loc)
+
+	info, ok := ClosestLocalTotalSolarEclipse(date, lon, lat, height)
+	if !ok {
+		t.Fatal("expected to find closest local total solar eclipse")
+	}
+	if info.Type != SolarEclipseTotal || !info.HasTotal {
+		t.Fatalf("unexpected closest total eclipse: %+v", info)
+	}
+	assertSolarTimeClose(t, "ClosestLocalTotalSolarEclipse", info.GreatestEclipse, time.Date(2024, 4, 8, 18, 17, 15, 0, loc), time.Minute)
+}
+
+func TestLocalAnnularSolarEclipseSearch(t *testing.T) {
+	loc := time.UTC
+	lon, lat, height := -114.5, -22.0, 0.0
+	date := time.Date(2024, 10, 1, 0, 0, 0, 0, loc)
+
+	next, ok := NextLocalAnnularSolarEclipse(date, lon, lat, height)
+	if !ok {
+		t.Fatal("expected to find next local annular solar eclipse")
+	}
+	if next.Type != SolarEclipseAnnular || !next.HasAnnular || next.HasTotal {
+		t.Fatalf("unexpected next annular eclipse: %+v", next)
+	}
+	assertSolarTimeClose(t, "NextLocalAnnularSolarEclipse", next.GreatestEclipse, time.Date(2024, 10, 2, 18, 44, 59, 0, loc), time.Minute)
+	assertSolarDurationClose(t, "NextLocalAnnularSolarEclipse duration", next.CentralEnd.Sub(next.CentralStart), 7*time.Minute+25*time.Second, 5*time.Second)
+
+	last, ok := LastLocalAnnularSolarEclipse(next.GreatestEclipse, lon, lat, height)
+	if !ok {
+		t.Fatal("expected to find previous local annular solar eclipse")
+	}
+	if last.Type != SolarEclipseAnnular || !last.HasAnnular || last.HasTotal {
+		t.Fatalf("unexpected last annular eclipse: %+v", last)
+	}
+	assertSolarTimeClose(t, "LastLocalAnnularSolarEclipse", last.GreatestEclipse, next.GreatestEclipse, time.Second)
+}
+
+func TestLocalAnnularSolarEclipseClosest(t *testing.T) {
+	loc := time.UTC
+	lon, lat, height := -114.5, -22.0, 0.0
+	date := time.Date(2024, 10, 2, 12, 0, 0, 0, loc)
+
+	info, ok := ClosestLocalAnnularSolarEclipse(date, lon, lat, height)
+	if !ok {
+		t.Fatal("expected to find closest local annular solar eclipse")
+	}
+	if info.Type != SolarEclipseAnnular || !info.HasAnnular || info.HasTotal {
+		t.Fatalf("unexpected closest annular eclipse: %+v", info)
+	}
+	assertSolarTimeClose(t, "ClosestLocalAnnularSolarEclipse", info.GreatestEclipse, time.Date(2024, 10, 2, 18, 44, 59, 0, loc), time.Minute)
+}
+
+func TestLocalCentralSolarEclipseVisibleRequiresCentralPhaseVisibility(t *testing.T) {
+	info := LocalSolarEclipseInfo{
+		Type:              SolarEclipseTotal,
+		Longitude:         0,
+		Latitude:          0,
+		PartialStart:      time.Date(2024, 1, 1, 9, 0, 0, 0, time.UTC),
+		PartialEnd:        time.Date(2024, 1, 1, 15, 0, 0, 0, time.UTC),
+		CentralStart:      time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC),
+		CentralEnd:        time.Date(2024, 1, 1, 1, 0, 0, 0, time.UTC),
+		HasPartial:        true,
+		HasCentral:        true,
+		HasTotal:          true,
+		VisibleAtGreatest: false,
+	}
+	if !localSolarEclipseVisible(info) {
+		t.Fatalf("expected partial phase to be visible")
+	}
+	if localCentralSolarEclipseVisible(info) {
+		t.Fatalf("expected central phase below horizon to be rejected")
+	}
+
+	info.Type = SolarEclipseAnnular
+	info.HasTotal = false
+	info.HasAnnular = true
+	if localCentralSolarEclipseVisible(info) {
+		t.Fatalf("expected annular central phase below horizon to be rejected")
+	}
+}
+
 func TestLocalSolarEclipseInfoKeepsLocation(t *testing.T) {
 	loc := time.FixedZone("UTC+08", 8*3600)
 	lon, lat, height := -104.1, 25.3, 1234.0
@@ -354,3 +464,14 @@ func assertSameLocalSolarEclipse(t *testing.T, name string, got, want LocalSolar
 	}
 	assertSolarTimeClose(t, name+".GreatestEclipse", got.GreatestEclipse, want.GreatestEclipse, tolerance)
 }
+
+func assertSolarDurationClose(t *testing.T, name string, got, want, tolerance time.Duration) {
+	t.Helper()
+	diff := got - want
+	if diff < 0 {
+		diff = -diff
+	}
+	if diff > tolerance {
+		t.Fatalf("%s mismatch: got %v want %v diff=%v", name, got, want, diff)
+	}
+}

event_boundary_public_test.go

@@ -0,0 +1,100 @@
+package astro_test
+
+import (
+	"math"
+	"testing"
+	"time"
+
+	"b612.me/astro/basic"
+	"b612.me/astro/jupiter"
+	"b612.me/astro/mars"
+	"b612.me/astro/mercury"
+	"b612.me/astro/neptune"
+	"b612.me/astro/saturn"
+	"b612.me/astro/uranus"
+	"b612.me/astro/venus"
+)
+
+func TestPublicPlanetEventBoundaryIncludesCurrent(t *testing.T) {
+	type eventFuncs struct {
+		last func(time.Time) time.Time
+		next func(time.Time) time.Time
+	}
+
+	cases := []struct {
+		name    string
+		eventUT float64
+		funcs   eventFuncs
+	}{
+		{name: "MercuryConjunction", eventUT: basic.NextMercuryConjunction(eventBoundaryTT(2026)), funcs: eventFuncs{last: mercury.LastConjunction, next: mercury.NextConjunction}},
+		{name: "MercuryInferior", eventUT: basic.NextMercuryInferiorConjunctionInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: mercury.LastInferiorConjunction, next: mercury.NextInferiorConjunction}},
+		{name: "MercurySuperior", eventUT: basic.NextMercurySuperiorConjunctionInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: mercury.LastSuperiorConjunction, next: mercury.NextSuperiorConjunction}},
+		{name: "MercuryRetrograde", eventUT: basic.NextMercuryRetrogradeInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: mercury.LastRetrograde, next: mercury.NextRetrograde}},
+		{name: "MercuryP2R", eventUT: basic.NextMercuryProgradeToRetrogradeInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: mercury.LastProgradeToRetrograde, next: mercury.NextProgradeToRetrograde}},
+		{name: "MercuryR2P", eventUT: basic.NextMercuryRetrogradeToProgradeInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: mercury.LastRetrogradeToPrograde, next: mercury.NextRetrogradeToPrograde}},
+		{name: "MercuryGreatestElongation", eventUT: basic.NextMercuryGreatestElongationInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: mercury.LastGreatestElongation, next: mercury.NextGreatestElongation}},
+		{name: "MercuryGreatestElongationEast", eventUT: basic.NextMercuryGreatestElongationEastInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: mercury.LastGreatestElongationEast, next: mercury.NextGreatestElongationEast}},
+		{name: "MercuryGreatestElongationWest", eventUT: basic.NextMercuryGreatestElongationWestInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: mercury.LastGreatestElongationWest, next: mercury.NextGreatestElongationWest}},
+
+		{name: "VenusConjunction", eventUT: basic.NextVenusConjunction(eventBoundaryTT(2026)), funcs: eventFuncs{last: venus.LastConjunction, next: venus.NextConjunction}},
+		{name: "VenusInferior", eventUT: basic.NextVenusInferiorConjunctionInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: venus.LastInferiorConjunction, next: venus.NextInferiorConjunction}},
+		{name: "VenusSuperior", eventUT: basic.NextVenusSuperiorConjunctionInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: venus.LastSuperiorConjunction, next: venus.NextSuperiorConjunction}},
+		{name: "VenusRetrograde", eventUT: basic.NextVenusRetrogradeInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: venus.LastRetrograde, next: venus.NextRetrograde}},
+		{name: "VenusP2R", eventUT: basic.NextVenusProgradeToRetrogradeInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: venus.LastProgradeToRetrograde, next: venus.NextProgradeToRetrograde}},
+		{name: "VenusR2P", eventUT: basic.NextVenusRetrogradeToProgradeInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: venus.LastRetrogradeToPrograde, next: venus.NextRetrogradeToPrograde}},
+		{name: "VenusGreatestElongation", eventUT: basic.NextVenusGreatestElongationInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: venus.LastGreatestElongation, next: venus.NextGreatestElongation}},
+		{name: "VenusGreatestElongationEast", eventUT: basic.NextVenusGreatestElongationEastInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: venus.LastGreatestElongationEast, next: venus.NextGreatestElongationEast}},
+		{name: "VenusGreatestElongationWest", eventUT: basic.NextVenusGreatestElongationWestInclusive(eventBoundaryTT(2026)), funcs: eventFuncs{last: venus.LastGreatestElongationWest, next: venus.NextGreatestElongationWest}},
+
+		{name: "MarsConjunction", eventUT: basic.NextMarsConjunction(eventBoundaryTT(2026)), funcs: eventFuncs{last: mars.LastConjunction, next: mars.NextConjunction}},
+		{name: "MarsOpposition", eventUT: basic.NextMarsOpposition(eventBoundaryTT(2026)), funcs: eventFuncs{last: mars.LastOpposition, next: mars.NextOpposition}},
+		{name: "MarsP2R", eventUT: basic.NextMarsProgradeToRetrograde(eventBoundaryTT(2026)), funcs: eventFuncs{last: mars.LastProgradeToRetrograde, next: mars.NextProgradeToRetrograde}},
+		{name: "MarsR2P", eventUT: basic.NextMarsRetrogradeToPrograde(eventBoundaryTT(2025)), funcs: eventFuncs{last: mars.LastRetrogradeToPrograde, next: mars.NextRetrogradeToPrograde}},
+		{name: "MarsEasternQuadrature", eventUT: basic.NextMarsEasternQuadrature(eventBoundaryTT(2026)), funcs: eventFuncs{last: mars.LastEasternQuadrature, next: mars.NextEasternQuadrature}},
+		{name: "MarsWesternQuadrature", eventUT: basic.NextMarsWesternQuadrature(eventBoundaryTT(2026)), funcs: eventFuncs{last: mars.LastWesternQuadrature, next: mars.NextWesternQuadrature}},
+
+		{name: "JupiterConjunction", eventUT: basic.NextJupiterConjunction(eventBoundaryTT(2026)), funcs: eventFuncs{last: jupiter.LastConjunction, next: jupiter.NextConjunction}},
+		{name: "JupiterOpposition", eventUT: basic.NextJupiterOpposition(eventBoundaryTT(2026)), funcs: eventFuncs{last: jupiter.LastOpposition, next: jupiter.NextOpposition}},
+		{name: "JupiterP2R", eventUT: basic.NextJupiterProgradeToRetrograde(eventBoundaryTT(2026)), funcs: eventFuncs{last: jupiter.LastProgradeToRetrograde, next: jupiter.NextProgradeToRetrograde}},
+		{name: "JupiterR2P", eventUT: basic.NextJupiterRetrogradeToPrograde(eventBoundaryTT(2026)), funcs: eventFuncs{last: jupiter.LastRetrogradeToPrograde, next: jupiter.NextRetrogradeToPrograde}},
+		{name: "JupiterEasternQuadrature", eventUT: basic.NextJupiterEasternQuadrature(eventBoundaryTT(2026)), funcs: eventFuncs{last: jupiter.LastEasternQuadrature, next: jupiter.NextEasternQuadrature}},
+		{name: "JupiterWesternQuadrature", eventUT: basic.NextJupiterWesternQuadrature(eventBoundaryTT(2026)), funcs: eventFuncs{last: jupiter.LastWesternQuadrature, next: jupiter.NextWesternQuadrature}},
+
+		{name: "SaturnOpposition", eventUT: basic.NextSaturnOpposition(eventBoundaryTT(2025)), funcs: eventFuncs{last: saturn.LastOpposition, next: saturn.NextOpposition}},
+		{name: "SaturnP2R", eventUT: basic.NextSaturnProgradeToRetrograde(eventBoundaryTT(2025)), funcs: eventFuncs{last: saturn.LastProgradeToRetrograde, next: saturn.NextProgradeToRetrograde}},
+		{name: "SaturnR2P", eventUT: basic.NextSaturnRetrogradeToPrograde(eventBoundaryTT(2025)), funcs: eventFuncs{last: saturn.LastRetrogradeToPrograde, next: saturn.NextRetrogradeToPrograde}},
+		{name: "SaturnEasternQuadrature", eventUT: basic.NextSaturnEasternQuadrature(eventBoundaryTT(2025)), funcs: eventFuncs{last: saturn.LastEasternQuadrature, next: saturn.NextEasternQuadrature}},
+		{name: "SaturnWesternQuadrature", eventUT: basic.NextSaturnWesternQuadrature(eventBoundaryTT(2025)), funcs: eventFuncs{last: saturn.LastWesternQuadrature, next: saturn.NextWesternQuadrature}},
+
+		{name: "UranusOpposition", eventUT: basic.NextUranusOpposition(eventBoundaryTT(2025)), funcs: eventFuncs{last: uranus.LastOpposition, next: uranus.NextOpposition}},
+		{name: "UranusP2R", eventUT: basic.NextUranusProgradeToRetrograde(eventBoundaryTT(2025)), funcs: eventFuncs{last: uranus.LastProgradeToRetrograde, next: uranus.NextProgradeToRetrograde}},
+		{name: "UranusR2P", eventUT: basic.NextUranusRetrogradeToPrograde(eventBoundaryTT(2025)), funcs: eventFuncs{last: uranus.LastRetrogradeToPrograde, next: uranus.NextRetrogradeToPrograde}},
+		{name: "UranusEasternQuadrature", eventUT: basic.NextUranusEasternQuadrature(eventBoundaryTT(2025)), funcs: eventFuncs{last: uranus.LastEasternQuadrature, next: uranus.NextEasternQuadrature}},
+		{name: "UranusWesternQuadrature", eventUT: basic.NextUranusWesternQuadrature(eventBoundaryTT(2025)), funcs: eventFuncs{last: uranus.LastWesternQuadrature, next: uranus.NextWesternQuadrature}},
+
+		{name: "NeptuneOpposition", eventUT: basic.NextNeptuneOpposition(eventBoundaryTT(2026)), funcs: eventFuncs{last: neptune.LastOpposition, next: neptune.NextOpposition}},
+		{name: "NeptuneP2R", eventUT: basic.NextNeptuneProgradeToRetrograde(eventBoundaryTT(2026)), funcs: eventFuncs{last: neptune.LastProgradeToRetrograde, next: neptune.NextProgradeToRetrograde}},
+		{name: "NeptuneR2P", eventUT: basic.NextNeptuneRetrogradeToPrograde(eventBoundaryTT(2026)), funcs: eventFuncs{last: neptune.LastRetrogradeToPrograde, next: neptune.NextRetrogradeToPrograde}},
+		{name: "NeptuneEasternQuadrature", eventUT: basic.NextNeptuneEasternQuadrature(eventBoundaryTT(2026)), funcs: eventFuncs{last: neptune.LastEasternQuadrature, next: neptune.NextEasternQuadrature}},
+		{name: "NeptuneWesternQuadrature", eventUT: basic.NextNeptuneWesternQuadrature(eventBoundaryTT(2026)), funcs: eventFuncs{last: neptune.LastWesternQuadrature, next: neptune.NextWesternQuadrature}},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			eventTime := basic.JDE2DateByZone(tc.eventUT, time.UTC, false)
+			assertSameEventTime(t, "last", tc.funcs.last(eventTime), eventTime)
+			assertSameEventTime(t, "next", tc.funcs.next(eventTime), eventTime)
+		})
+	}
+}
+
+func eventBoundaryTT(year int) float64 {
+	return basic.TD2UT(basic.Date2JDE(time.Date(year, 1, 1, 0, 0, 0, 0, time.UTC)), true)
+}
+
+func assertSameEventTime(t *testing.T, name string, got, want time.Time) {
+	t.Helper()
+	if math.Abs(got.Sub(want).Seconds()) > 1.0 {
+		t.Fatalf("%s boundary mismatch: got %s want %s delta %.3fs", name, got, want, got.Sub(want).Seconds())
+	}
+}

jupiter/jupiter.go

@@ -207,8 +207,7 @@ func SetTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, er
 
 // LastConjunction 上一次合日 / previous conjunction with the Sun.
 //
-// 返回 date 之前最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the most recent conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次与太阳的合日时刻，结果保持 date 的时区。
 func LastConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastJupiterConjunction(jde), date.Location(), false)
@@ -216,8 +215,7 @@ func LastConjunction(date time.Time) time.Time {
 
 // NextConjunction 下一次合日 / next conjunction with the Sun.
 //
-// 返回 date 之后最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the next conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次与太阳的合日时刻，结果保持 date 的时区。
 func NextConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextJupiterConjunction(jde), date.Location(), false)
@@ -225,8 +223,7 @@ func NextConjunction(date time.Time) time.Time {
 
 // LastOpposition 上一次冲日 / previous opposition.
 //
-// 返回 date 之前最近一次冲日时刻，结果保持 date 的时区。
-// Returns the most recent opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次冲日时刻，结果保持 date 的时区。
 func LastOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastJupiterOpposition(jde), date.Location(), false)
@@ -234,8 +231,7 @@ func LastOpposition(date time.Time) time.Time {
 
 // NextOpposition 下一次冲日 / next opposition.
 //
-// 返回 date 之后最近一次冲日时刻，结果保持 date 的时区。
-// Returns the next opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次冲日时刻，结果保持 date 的时区。
 func NextOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextJupiterOpposition(jde), date.Location(), false)
@@ -243,8 +239,7 @@ func NextOpposition(date time.Time) time.Time {
 
 // LastProgradeToRetrograde 上一次顺行转逆行留 / previous station from prograde to retrograde.
 //
-// 返回 date 之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func LastProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastJupiterProgradeToRetrograde(jde), date.Location(), false)
@@ -252,8 +247,7 @@ func LastProgradeToRetrograde(date time.Time) time.Time {
 
 // NextProgradeToRetrograde 下一次顺行转逆行留 / next station from prograde to retrograde.
 //
-// 返回 date 之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func NextProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextJupiterProgradeToRetrograde(jde), date.Location(), false)
@@ -261,8 +255,7 @@ func NextProgradeToRetrograde(date time.Time) time.Time {
 
 // LastRetrogradeToPrograde 上一次逆行转顺行留 / previous station from retrograde to prograde.
 //
-// 返回 date 之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func LastRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastJupiterRetrogradeToPrograde(jde), date.Location(), false)
@@ -270,8 +263,7 @@ func LastRetrogradeToPrograde(date time.Time) time.Time {
 
 // NextRetrogradeToPrograde 下一次逆行转顺行留 / next station from retrograde to prograde.
 //
-// 返回 date 之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func NextRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextJupiterRetrogradeToPrograde(jde), date.Location(), false)
@@ -279,8 +271,7 @@ func NextRetrogradeToPrograde(date time.Time) time.Time {
 
 // LastEasternQuadrature 上一次东方照 / previous eastern quadrature.
 //
-// 返回 date 之前最近一次东方照时刻，结果保持 date 的时区。
-// Returns the most recent eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次东方照时刻，结果保持 date 的时区。
 func LastEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastJupiterEasternQuadrature(jde), date.Location(), false)
@@ -288,8 +279,7 @@ func LastEasternQuadrature(date time.Time) time.Time {
 
 // NextEasternQuadrature 下一次东方照 / next eastern quadrature.
 //
-// 返回 date 之后最近一次东方照时刻，结果保持 date 的时区。
-// Returns the next eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次东方照时刻，结果保持 date 的时区。
 func NextEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextJupiterEasternQuadrature(jde), date.Location(), false)
@@ -297,8 +287,7 @@ func NextEasternQuadrature(date time.Time) time.Time {
 
 // LastWesternQuadrature 上一次西方照 / previous western quadrature.
 //
-// 返回 date 之前最近一次西方照时刻，结果保持 date 的时区。
-// Returns the most recent western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次西方照时刻，结果保持 date 的时区。
 func LastWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastJupiterWesternQuadrature(jde), date.Location(), false)
@@ -306,8 +295,7 @@ func LastWesternQuadrature(date time.Time) time.Time {
 
 // NextWesternQuadrature 下一次西方照 / next western quadrature.
 //
-// 返回 date 之后最近一次西方照时刻，结果保持 date 的时区。
-// Returns the next western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次西方照时刻，结果保持 date 的时区。
 func NextWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextJupiterWesternQuadrature(jde), date.Location(), false)

mars/mars.go

@@ -207,8 +207,7 @@ func SetTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, er
 
 // LastConjunction 上一次合日 / previous conjunction with the Sun.
 //
-// 返回 date 之前最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the most recent conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次与太阳的合日时刻，结果保持 date 的时区。
 func LastConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastMarsConjunction(jde), date.Location(), false)
@@ -216,8 +215,7 @@ func LastConjunction(date time.Time) time.Time {
 
 // NextConjunction 下一次合日 / next conjunction with the Sun.
 //
-// 返回 date 之后最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the next conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次与太阳的合日时刻，结果保持 date 的时区。
 func NextConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextMarsConjunction(jde), date.Location(), false)
@@ -225,8 +223,7 @@ func NextConjunction(date time.Time) time.Time {
 
 // LastOpposition 上一次冲日 / previous opposition.
 //
-// 返回 date 之前最近一次冲日时刻，结果保持 date 的时区。
-// Returns the most recent opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次冲日时刻，结果保持 date 的时区。
 func LastOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastMarsOpposition(jde), date.Location(), false)
@@ -234,8 +231,7 @@ func LastOpposition(date time.Time) time.Time {
 
 // NextOpposition 下一次冲日 / next opposition.
 //
-// 返回 date 之后最近一次冲日时刻，结果保持 date 的时区。
-// Returns the next opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次冲日时刻，结果保持 date 的时区。
 func NextOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextMarsOpposition(jde), date.Location(), false)
@@ -243,8 +239,7 @@ func NextOpposition(date time.Time) time.Time {
 
 // LastProgradeToRetrograde 上一次顺行转逆行留 / previous station from prograde to retrograde.
 //
-// 返回 date 之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func LastProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastMarsProgradeToRetrograde(jde), date.Location(), false)
@@ -252,8 +247,7 @@ func LastProgradeToRetrograde(date time.Time) time.Time {
 
 // NextProgradeToRetrograde 下一次顺行转逆行留 / next station from prograde to retrograde.
 //
-// 返回 date 之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func NextProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextMarsProgradeToRetrograde(jde), date.Location(), false)
@@ -261,8 +255,7 @@ func NextProgradeToRetrograde(date time.Time) time.Time {
 
 // LastRetrogradeToPrograde 上一次逆行转顺行留 / previous station from retrograde to prograde.
 //
-// 返回 date 之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func LastRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastMarsRetrogradeToPrograde(jde), date.Location(), false)
@@ -270,8 +263,7 @@ func LastRetrogradeToPrograde(date time.Time) time.Time {
 
 // NextRetrogradeToPrograde 下一次逆行转顺行留 / next station from retrograde to prograde.
 //
-// 返回 date 之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func NextRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextMarsRetrogradeToPrograde(jde), date.Location(), false)
@@ -279,8 +271,7 @@ func NextRetrogradeToPrograde(date time.Time) time.Time {
 
 // LastEasternQuadrature 上一次东方照 / previous eastern quadrature.
 //
-// 返回 date 之前最近一次东方照时刻，结果保持 date 的时区。
-// Returns the most recent eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次东方照时刻，结果保持 date 的时区。
 func LastEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastMarsEasternQuadrature(jde), date.Location(), false)
@@ -288,8 +279,7 @@ func LastEasternQuadrature(date time.Time) time.Time {
 
 // NextEasternQuadrature 下一次东方照 / next eastern quadrature.
 //
-// 返回 date 之后最近一次东方照时刻，结果保持 date 的时区。
-// Returns the next eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次东方照时刻，结果保持 date 的时区。
 func NextEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextMarsEasternQuadrature(jde), date.Location(), false)
@@ -297,8 +287,7 @@ func NextEasternQuadrature(date time.Time) time.Time {
 
 // LastWesternQuadrature 上一次西方照 / previous western quadrature.
 //
-// 返回 date 之前最近一次西方照时刻，结果保持 date 的时区。
-// Returns the most recent western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次西方照时刻，结果保持 date 的时区。
 func LastWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastMarsWesternQuadrature(jde), date.Location(), false)
@@ -306,8 +295,7 @@ func LastWesternQuadrature(date time.Time) time.Time {
 
 // NextWesternQuadrature 下一次西方照 / next western quadrature.
 //
-// 返回 date 之后最近一次西方照时刻，结果保持 date 的时区。
-// Returns the next western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次西方照时刻，结果保持 date 的时区。
 func NextWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextMarsWesternQuadrature(jde), date.Location(), false)

mercury/mercury.go

@@ -207,8 +207,7 @@ func SetTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, er
 
 // LastConjunction 上一次合日 / previous conjunction with the Sun.
 //
-// 返回 date 之前最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the most recent conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次与太阳的合日时刻，结果保持 date 的时区。
 func LastConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastMercuryConjunction(jde), date.Location(), false)
@@ -216,8 +215,7 @@ func LastConjunction(date time.Time) time.Time {
 
 // NextConjunction 下一次合日 / next conjunction with the Sun.
 //
-// 返回 date 之后最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the next conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次与太阳的合日时刻，结果保持 date 的时区。
 func NextConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextMercuryConjunction(jde), date.Location(), false)
@@ -225,144 +223,128 @@ func NextConjunction(date time.Time) time.Time {
 
 // LastInferiorConjunction 上一次下合 / previous inferior conjunction.
 //
-// 返回 date 之前最近一次下合时刻，结果保持 date 的时区。
-// Returns the most recent inferior conjunction relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次下合时刻，结果保持 date 的时区。
 func LastInferiorConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastMercuryInferiorConjunction(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastMercuryInferiorConjunctionInclusive(jde), date.Location(), false)
 }
 
 // NextInferiorConjunction 下一次下合 / next inferior conjunction.
 //
-// 返回 date 之后最近一次下合时刻，结果保持 date 的时区。
-// Returns the next inferior conjunction relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次下合时刻，结果保持 date 的时区。
 func NextInferiorConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextMercuryInferiorConjunction(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextMercuryInferiorConjunctionInclusive(jde), date.Location(), false)
 }
 
 // LastSuperiorConjunction 上一次上合 / previous superior conjunction.
 //
-// 返回 date 之前最近一次上合时刻，结果保持 date 的时区。
-// Returns the most recent superior conjunction relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次上合时刻，结果保持 date 的时区。
 func LastSuperiorConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastMercurySuperiorConjunction(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastMercurySuperiorConjunctionInclusive(jde), date.Location(), false)
 }
 
 // NextSuperiorConjunction 下一次上合 / next superior conjunction.
 //
-// 返回 date 之后最近一次上合时刻，结果保持 date 的时区。
-// Returns the next superior conjunction relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次上合时刻，结果保持 date 的时区。
 func NextSuperiorConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextMercurySuperiorConjunction(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextMercurySuperiorConjunctionInclusive(jde), date.Location(), false)
 }
 
 // LastRetrograde 上一次留 / previous stationary point.
 //
-// 返回 date 之前最近一次留时刻，不区分顺转逆还是逆转顺，结果保持 date 的时区。
-// Returns the most recent stationary point relative to date without distinguishing direction, keeping date's time zone.
+// 返回 date 当前或之前最近一次留时刻，不区分顺转逆还是逆转顺，结果保持 date 的时区。
 func LastRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastMercuryRetrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastMercuryRetrogradeInclusive(jde), date.Location(), false)
 }
 
 // NextRetrograde 下一次留 / next stationary point.
 //
-// 返回 date 之后最近一次留时刻，不区分顺转逆还是逆转顺，结果保持 date 的时区。
-// Returns the next stationary point relative to date without distinguishing direction, keeping date's time zone.
+// 返回 date 当前或之后最近一次留时刻，不区分顺转逆还是逆转顺，结果保持 date 的时区。
 func NextRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextMercuryRetrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextMercuryRetrogradeInclusive(jde), date.Location(), false)
 }
 
 // LastProgradeToRetrograde 上一次顺行转逆行留 / previous station from prograde to retrograde.
 //
-// 返回 date 之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func LastProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastMercuryProgradeToRetrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastMercuryProgradeToRetrogradeInclusive(jde), date.Location(), false)
 }
 
 // NextProgradeToRetrograde 下一次顺行转逆行留 / next station from prograde to retrograde.
 //
-// 返回 date 之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func NextProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextMercuryProgradeToRetrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextMercuryProgradeToRetrogradeInclusive(jde), date.Location(), false)
 }
 
 // LastRetrogradeToPrograde 上一次逆行转顺行留 / previous station from retrograde to prograde.
 //
-// 返回 date 之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func LastRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastMercuryRetrogradeToPrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastMercuryRetrogradeToProgradeInclusive(jde), date.Location(), false)
 }
 
 // NextRetrogradeToPrograde 下一次逆行转顺行留 / next station from retrograde to prograde.
 //
-// 返回 date 之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func NextRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextMercuryRetrogradeToPrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextMercuryRetrogradeToProgradeInclusive(jde), date.Location(), false)
 }
 
 // LastGreatestElongation 上一次大距 / previous greatest elongation.
 //
-// 返回 date 之前最近一次大距时刻，不区分东西大距，结果保持 date 的时区。
-// Returns the most recent greatest elongation relative to date without distinguishing east or west, keeping date's time zone.
+// 返回 date 当前或之前最近一次大距时刻，不区分东西大距，结果保持 date 的时区。
 func LastGreatestElongation(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastMercuryGreatestElongation(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastMercuryGreatestElongationInclusive(jde), date.Location(), false)
 }
 
 // NextGreatestElongation 下一次大距 / next greatest elongation.
 //
-// 返回 date 之后最近一次大距时刻，不区分东西大距，结果保持 date 的时区。
-// Returns the next greatest elongation relative to date without distinguishing east or west, keeping date's time zone.
+// 返回 date 当前或之后最近一次大距时刻，不区分东西大距，结果保持 date 的时区。
 func NextGreatestElongation(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextMercuryGreatestElongation(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextMercuryGreatestElongationInclusive(jde), date.Location(), false)
 }
 
 // LastGreatestElongationEast 上一次东大距 / previous greatest eastern elongation.
 //
-// 返回 date 之前最近一次东大距时刻，结果保持 date 的时区。
-// Returns the most recent greatest eastern elongation relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次东大距时刻，结果保持 date 的时区。
 func LastGreatestElongationEast(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastMercuryGreatestElongationEast(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastMercuryGreatestElongationEastInclusive(jde), date.Location(), false)
 }
 
 // NextGreatestElongationEast 下一次东大距 / next greatest eastern elongation.
 //
-// 返回 date 之后最近一次东大距时刻，结果保持 date 的时区。
-// Returns the next greatest eastern elongation relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次东大距时刻，结果保持 date 的时区。
 func NextGreatestElongationEast(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextMercuryGreatestElongationEast(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextMercuryGreatestElongationEastInclusive(jde), date.Location(), false)
 }
 
 // LastGreatestElongationWest 上一次西大距 / previous greatest western elongation.
 //
-// 返回 date 之前最近一次西大距时刻，结果保持 date 的时区。
-// Returns the most recent greatest western elongation relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次西大距时刻，结果保持 date 的时区。
 func LastGreatestElongationWest(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastMercuryGreatestElongationWest(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastMercuryGreatestElongationWestInclusive(jde), date.Location(), false)
 }
 
 // NextGreatestElongationWest 下一次西大距 / next greatest western elongation.
 //
-// 返回 date 之后最近一次西大距时刻，结果保持 date 的时区。
-// Returns the next greatest western elongation relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次西大距时刻，结果保持 date 的时区。
 func NextGreatestElongationWest(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextMercuryGreatestElongationWest(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextMercuryGreatestElongationWestInclusive(jde), date.Location(), false)
 }

mercury/transit.go

@@ -0,0 +1,73 @@
+package mercury
+
+import (
+	"time"
+
+	"b612.me/astro/basic"
+)
+
+// TransitInfo 地心水星凌日信息 / geocentric Mercury transit information.
+//
+// Start、Greatest、End、InternalStart、InternalEnd 都保持调用者输入的时区。
+// 内切接触不存在时 InternalStart / InternalEnd 为零值。
+// Start, Greatest, End, InternalStart, and InternalEnd preserve the caller's timezone.
+// InternalStart and InternalEnd are zero values when internal contacts do not exist.
+type TransitInfo struct {
+	Valid bool
+
+	Start         time.Time
+	InternalStart time.Time
+	Greatest      time.Time
+	InternalEnd   time.Time
+	End           time.Time
+
+	Duration         time.Duration
+	InternalDuration time.Duration
+
+	MinimumSeparationArcsec  float64
+	SunSemidiameterArcsec    float64
+	PlanetSemidiameterArcsec float64
+
+	HasInternal bool
+}
+
+// NextTransit 下一次地心水星凌日 / next geocentric Mercury transit.
+func NextTransit(date time.Time) TransitInfo {
+	return transitInfoFromBasic(basic.NextMercuryTransit(basic.Date2JDE(date.UTC())), date.Location())
+}
+
+// LastTransit 上一次地心水星凌日 / previous geocentric Mercury transit.
+func LastTransit(date time.Time) TransitInfo {
+	return transitInfoFromBasic(basic.LastMercuryTransit(basic.Date2JDE(date.UTC())), date.Location())
+}
+
+// ClosestTransit 最近一次地心水星凌日 / closest geocentric Mercury transit.
+func ClosestTransit(date time.Time) TransitInfo {
+	return transitInfoFromBasic(basic.ClosestMercuryTransit(basic.Date2JDE(date.UTC())), date.Location())
+}
+
+func transitInfoFromBasic(result basic.PlanetTransitResult, loc *time.Location) TransitInfo {
+	if !result.Valid {
+		return TransitInfo{}
+	}
+	start := basic.JDE2DateByZone(result.ExternalIngress, loc, false)
+	greatest := basic.JDE2DateByZone(result.Greatest, loc, false)
+	end := basic.JDE2DateByZone(result.ExternalEgress, loc, false)
+	info := TransitInfo{
+		Valid:                    true,
+		Start:                    start,
+		Greatest:                 greatest,
+		End:                      end,
+		Duration:                 end.Sub(start),
+		MinimumSeparationArcsec:  result.MinimumSeparationArcsec,
+		SunSemidiameterArcsec:    result.SunSemidiameterArcsec,
+		PlanetSemidiameterArcsec: result.PlanetSemidiameterArcsec,
+		HasInternal:              result.HasInternal,
+	}
+	if result.HasInternal {
+		info.InternalStart = basic.JDE2DateByZone(result.InternalIngress, loc, false)
+		info.InternalEnd = basic.JDE2DateByZone(result.InternalEgress, loc, false)
+		info.InternalDuration = info.InternalEnd.Sub(info.InternalStart)
+	}
+	return info
+}

mercury/transit_test.go

@@ -0,0 +1,23 @@
+package mercury
+
+import (
+	"testing"
+	"time"
+)
+
+func TestTransitWrappers(t *testing.T) {
+	loc := time.FixedZone("CST", 8*3600)
+	info := NextTransit(time.Date(2019, 1, 1, 0, 0, 0, 0, loc))
+	if !info.Valid {
+		t.Fatal("expected valid transit")
+	}
+	if info.Greatest.Location() != loc {
+		t.Fatalf("timezone mismatch: got %v want %v", info.Greatest.Location(), loc)
+	}
+	if info.Greatest.Year() != 2019 || info.Greatest.Month() != time.November || info.Greatest.Day() != 11 {
+		t.Fatalf("unexpected greatest time: %s", info.Greatest)
+	}
+	if !info.HasInternal || info.Duration <= 0 || info.InternalDuration <= 0 {
+		t.Fatalf("unexpected durations: %+v", info)
+	}
+}

neptune/neptune.go

@@ -207,8 +207,7 @@ func SetTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, er
 
 // LastConjunction 上一次合日 / previous conjunction with the Sun.
 //
-// 返回 date 之前最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the most recent conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次与太阳的合日时刻，结果保持 date 的时区。
 func LastConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastNeptuneConjunction(jde), date.Location(), false)
@@ -216,8 +215,7 @@ func LastConjunction(date time.Time) time.Time {
 
 // NextConjunction 下一次合日 / next conjunction with the Sun.
 //
-// 返回 date 之后最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the next conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次与太阳的合日时刻，结果保持 date 的时区。
 func NextConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextNeptuneConjunction(jde), date.Location(), false)
@@ -225,8 +223,7 @@ func NextConjunction(date time.Time) time.Time {
 
 // LastOpposition 上一次冲日 / previous opposition.
 //
-// 返回 date 之前最近一次冲日时刻，结果保持 date 的时区。
-// Returns the most recent opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次冲日时刻，结果保持 date 的时区。
 func LastOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastNeptuneOpposition(jde), date.Location(), false)
@@ -234,8 +231,7 @@ func LastOpposition(date time.Time) time.Time {
 
 // NextOpposition 下一次冲日 / next opposition.
 //
-// 返回 date 之后最近一次冲日时刻，结果保持 date 的时区。
-// Returns the next opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次冲日时刻，结果保持 date 的时区。
 func NextOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextNeptuneOpposition(jde), date.Location(), false)
@@ -243,8 +239,7 @@ func NextOpposition(date time.Time) time.Time {
 
 // LastProgradeToRetrograde 上一次顺行转逆行留 / previous station from prograde to retrograde.
 //
-// 返回 date 之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func LastProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastNeptuneProgradeToRetrograde(jde), date.Location(), false)
@@ -252,8 +247,7 @@ func LastProgradeToRetrograde(date time.Time) time.Time {
 
 // NextProgradeToRetrograde 下一次顺行转逆行留 / next station from prograde to retrograde.
 //
-// 返回 date 之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func NextProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextNeptuneProgradeToRetrograde(jde), date.Location(), false)
@@ -261,8 +255,7 @@ func NextProgradeToRetrograde(date time.Time) time.Time {
 
 // LastRetrogradeToPrograde 上一次逆行转顺行留 / previous station from retrograde to prograde.
 //
-// 返回 date 之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func LastRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastNeptuneRetrogradeToPrograde(jde), date.Location(), false)
@@ -270,8 +263,7 @@ func LastRetrogradeToPrograde(date time.Time) time.Time {
 
 // NextRetrogradeToPrograde 下一次逆行转顺行留 / next station from retrograde to prograde.
 //
-// 返回 date 之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func NextRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextNeptuneRetrogradeToPrograde(jde), date.Location(), false)
@@ -279,8 +271,7 @@ func NextRetrogradeToPrograde(date time.Time) time.Time {
 
 // LastEasternQuadrature 上一次东方照 / previous eastern quadrature.
 //
-// 返回 date 之前最近一次东方照时刻，结果保持 date 的时区。
-// Returns the most recent eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次东方照时刻，结果保持 date 的时区。
 func LastEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastNeptuneEasternQuadrature(jde), date.Location(), false)
@@ -288,8 +279,7 @@ func LastEasternQuadrature(date time.Time) time.Time {
 
 // NextEasternQuadrature 下一次东方照 / next eastern quadrature.
 //
-// 返回 date 之后最近一次东方照时刻，结果保持 date 的时区。
-// Returns the next eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次东方照时刻，结果保持 date 的时区。
 func NextEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextNeptuneEasternQuadrature(jde), date.Location(), false)
@@ -297,8 +287,7 @@ func NextEasternQuadrature(date time.Time) time.Time {
 
 // LastWesternQuadrature 上一次西方照 / previous western quadrature.
 //
-// 返回 date 之前最近一次西方照时刻，结果保持 date 的时区。
-// Returns the most recent western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次西方照时刻，结果保持 date 的时区。
 func LastWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastNeptuneWesternQuadrature(jde), date.Location(), false)
@@ -306,8 +295,7 @@ func LastWesternQuadrature(date time.Time) time.Time {
 
 // NextWesternQuadrature 下一次西方照 / next western quadrature.
 //
-// 返回 date 之后最近一次西方照时刻，结果保持 date 的时区。
-// Returns the next western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次西方照时刻，结果保持 date 的时区。
 func NextWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextNeptuneWesternQuadrature(jde), date.Location(), false)

neptune/neptune_test.go

@@ -1,14 +1,19 @@
 package neptune
 
 import (
+	"math"
 	"testing"
 	"time"
 )
 
+func sameUnixSecond(got time.Time, want int64) bool {
+	return math.Abs(float64(got.Unix()-want)) <= 1
+}
+
 func TestNeptune(t *testing.T) {
 	tz := time.FixedZone("CST", 8*3600)
 	date := time.Date(2022, 01, 20, 00, 00, 00, 00, tz)
-	if NextConjunction(date).Unix() != 1647171800 {
+	if !sameUnixSecond(NextConjunction(date), 1647171800) {
 		t.Fatal(NextConjunction(date).Unix())
 	}
 	if CulminationTime(date, 115).Unix() != 1642665021 {

planet/planet.go

@@ -25,7 +25,7 @@ func WherePlanetN(xt, zn int, jd float64, n int) float64 {
 	t := (jd - 2451545) / 36525.0000
 	t /= 10 // 转为儒略千年数
 
-	body := planetViews[xt]
+	body := planetViews()[xt]
 	coord := body.coords[zn]
 	baseOrderTerms := len(coord.orders[0])
 

planet/planet_test.go

@@ -25,8 +25,9 @@ func TestWherePlanetNFullMatchesDefault(t *testing.T) {
 }
 
 func TestPlanetViewsMatchRawCuts(t *testing.T) {
+	views := planetViews()
 	for bodyIndex, raw := range planetRawData {
-		view := planetViews[bodyIndex]
+		view := views[bodyIndex]
 		if math.Float64bits(view.scale) != math.Float64bits(raw[0]) {
 			t.Fatalf("body=%d scale mismatch", bodyIndex)
 		}
@@ -42,3 +43,15 @@ func TestPlanetViewsMatchRawCuts(t *testing.T) {
 		}
 	}
 }
+
+func TestBuildPlanetViewsRejectsInvalidCuts(t *testing.T) {
+	_, err := buildPlanetViews([][]float64{{
+		10000000000,
+		20, 21, 20, 20, 20, 20, 20,
+		20, 20, 20, 20, 20, 20,
+		20, 20, 20, 20, 20, 20,
+	}})
+	if err == nil {
+		t.Fatal("expected invalid cut error")
+	}
+}

planet/view.go

@@ -1,6 +1,9 @@
 package planet
 
-import "fmt"
+import (
+	"fmt"
+	"sync"
+)
 
 type coordSeriesView struct {
 	orders [6][]float64
@@ -11,13 +14,27 @@ type planetView struct {
 	coords [3]coordSeriesView
 }
 
-var planetViews = buildPlanetViews(planetRawData)
+var (
+	planetViewsOnce  sync.Once
+	planetViewsCache []planetView
+	planetViewsErr   error
+)
 
-func buildPlanetViews(rawData [][]float64) []planetView {
+func planetViews() []planetView {
+	planetViewsOnce.Do(func() {
+		planetViewsCache, planetViewsErr = buildPlanetViews(planetRawData)
+	})
+	if planetViewsErr != nil {
+		panic(planetViewsErr)
+	}
+	return planetViewsCache
+}
+
+func buildPlanetViews(rawData [][]float64) ([]planetView, error) {
 	views := make([]planetView, len(rawData))
 	for bodyIndex, raw := range rawData {
 		if len(raw) < 20 {
-			panic(fmt.Sprintf("planet raw data %d too short: %d", bodyIndex, len(raw)))
+			return nil, fmt.Errorf("planet raw data %d too short: %d", bodyIndex, len(raw))
 		}
 		view := planetView{scale: raw[0]}
 		for zn := 0; zn < 3; zn++ {
@@ -26,12 +43,12 @@ func buildPlanetViews(rawData [][]float64) []planetView {
 				start := int(raw[pn+order])
 				end := int(raw[pn+order+1])
 				if start < 0 || end < start || end > len(raw) {
-					panic(fmt.Sprintf("planet raw data %d coord %d order %d invalid cut: %d..%d (len=%d)", bodyIndex, zn, order, start, end, len(raw)))
+					return nil, fmt.Errorf("planet raw data %d coord %d order %d invalid cut: %d..%d (len=%d)", bodyIndex, zn, order, start, end, len(raw))
 				}
 				view.coords[zn].orders[order] = raw[start:end]
 			}
 		}
 		views[bodyIndex] = view
 	}
-	return views
+	return views, nil
 }

saturn/saturn.go

@@ -207,8 +207,7 @@ func SetTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, er
 
 // LastConjunction 上一次合日 / previous conjunction with the Sun.
 //
-// 返回 date 之前最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the most recent conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次与太阳的合日时刻，结果保持 date 的时区。
 func LastConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnConjunction(jde), date.Location(), false)
@@ -216,8 +215,7 @@ func LastConjunction(date time.Time) time.Time {
 
 // NextConjunction 下一次合日 / next conjunction with the Sun.
 //
-// 返回 date 之后最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the next conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次与太阳的合日时刻，结果保持 date 的时区。
 func NextConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnConjunction(jde), date.Location(), false)
@@ -225,8 +223,7 @@ func NextConjunction(date time.Time) time.Time {
 
 // LastOpposition 上一次冲日 / previous opposition.
 //
-// 返回 date 之前最近一次冲日时刻，结果保持 date 的时区。
-// Returns the most recent opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次冲日时刻，结果保持 date 的时区。
 func LastOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnOpposition(jde), date.Location(), false)
@@ -234,8 +231,7 @@ func LastOpposition(date time.Time) time.Time {
 
 // NextOpposition 下一次冲日 / next opposition.
 //
-// 返回 date 之后最近一次冲日时刻，结果保持 date 的时区。
-// Returns the next opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次冲日时刻，结果保持 date 的时区。
 func NextOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnOpposition(jde), date.Location(), false)
@@ -243,8 +239,7 @@ func NextOpposition(date time.Time) time.Time {
 
 // LastProgradeToRetrograde 上一次顺行转逆行留 / previous station from prograde to retrograde.
 //
-// 返回 date 之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func LastProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnProgradeToRetrograde(jde), date.Location(), false)
@@ -252,8 +247,7 @@ func LastProgradeToRetrograde(date time.Time) time.Time {
 
 // NextProgradeToRetrograde 下一次顺行转逆行留 / next station from prograde to retrograde.
 //
-// 返回 date 之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func NextProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnProgradeToRetrograde(jde), date.Location(), false)
@@ -261,8 +255,7 @@ func NextProgradeToRetrograde(date time.Time) time.Time {
 
 // LastRetrogradeToPrograde 上一次逆行转顺行留 / previous station from retrograde to prograde.
 //
-// 返回 date 之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func LastRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnRetrogradeToPrograde(jde), date.Location(), false)
@@ -270,8 +263,7 @@ func LastRetrogradeToPrograde(date time.Time) time.Time {
 
 // NextRetrogradeToPrograde 下一次逆行转顺行留 / next station from retrograde to prograde.
 //
-// 返回 date 之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func NextRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnRetrogradeToPrograde(jde), date.Location(), false)
@@ -279,8 +271,7 @@ func NextRetrogradeToPrograde(date time.Time) time.Time {
 
 // LastEasternQuadrature 上一次东方照 / previous eastern quadrature.
 //
-// 返回 date 之前最近一次东方照时刻，结果保持 date 的时区。
-// Returns the most recent eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次东方照时刻，结果保持 date 的时区。
 func LastEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnEasternQuadrature(jde), date.Location(), false)
@@ -288,8 +279,7 @@ func LastEasternQuadrature(date time.Time) time.Time {
 
 // NextEasternQuadrature 下一次东方照 / next eastern quadrature.
 //
-// 返回 date 之后最近一次东方照时刻，结果保持 date 的时区。
-// Returns the next eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次东方照时刻，结果保持 date 的时区。
 func NextEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnEasternQuadrature(jde), date.Location(), false)
@@ -297,8 +287,7 @@ func NextEasternQuadrature(date time.Time) time.Time {
 
 // LastWesternQuadrature 上一次西方照 / previous western quadrature.
 //
-// 返回 date 之前最近一次西方照时刻，结果保持 date 的时区。
-// Returns the most recent western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次西方照时刻，结果保持 date 的时区。
 func LastWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastSaturnWesternQuadrature(jde), date.Location(), false)
@@ -306,8 +295,7 @@ func LastWesternQuadrature(date time.Time) time.Time {
 
 // NextWesternQuadrature 下一次西方照 / next western quadrature.
 //
-// 返回 date 之后最近一次西方照时刻，结果保持 date 的时区。
-// Returns the next western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次西方照时刻，结果保持 date 的时区。
 func NextWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextSaturnWesternQuadrature(jde), date.Location(), false)

uranus/uranus.go

@@ -207,8 +207,7 @@ func SetTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, er
 
 // LastConjunction 上一次合日 / previous conjunction with the Sun.
 //
-// 返回 date 之前最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the most recent conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次与太阳的合日时刻，结果保持 date 的时区。
 func LastConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastUranusConjunction(jde), date.Location(), false)
@@ -216,8 +215,7 @@ func LastConjunction(date time.Time) time.Time {
 
 // NextConjunction 下一次合日 / next conjunction with the Sun.
 //
-// 返回 date 之后最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the next conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次与太阳的合日时刻，结果保持 date 的时区。
 func NextConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextUranusConjunction(jde), date.Location(), false)
@@ -225,8 +223,7 @@ func NextConjunction(date time.Time) time.Time {
 
 // LastOpposition 上一次冲日 / previous opposition.
 //
-// 返回 date 之前最近一次冲日时刻，结果保持 date 的时区。
-// Returns the most recent opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次冲日时刻，结果保持 date 的时区。
 func LastOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastUranusOpposition(jde), date.Location(), false)
@@ -234,8 +231,7 @@ func LastOpposition(date time.Time) time.Time {
 
 // NextOpposition 下一次冲日 / next opposition.
 //
-// 返回 date 之后最近一次冲日时刻，结果保持 date 的时区。
-// Returns the next opposition relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次冲日时刻，结果保持 date 的时区。
 func NextOpposition(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextUranusOpposition(jde), date.Location(), false)
@@ -243,8 +239,7 @@ func NextOpposition(date time.Time) time.Time {
 
 // LastProgradeToRetrograde 上一次顺行转逆行留 / previous station from prograde to retrograde.
 //
-// 返回 date 之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func LastProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastUranusProgradeToRetrograde(jde), date.Location(), false)
@@ -252,8 +247,7 @@ func LastProgradeToRetrograde(date time.Time) time.Time {
 
 // NextProgradeToRetrograde 下一次顺行转逆行留 / next station from prograde to retrograde.
 //
-// 返回 date 之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func NextProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextUranusProgradeToRetrograde(jde), date.Location(), false)
@@ -261,8 +255,7 @@ func NextProgradeToRetrograde(date time.Time) time.Time {
 
 // LastRetrogradeToPrograde 上一次逆行转顺行留 / previous station from retrograde to prograde.
 //
-// 返回 date 之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func LastRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastUranusRetrogradeToPrograde(jde), date.Location(), false)
@@ -270,8 +263,7 @@ func LastRetrogradeToPrograde(date time.Time) time.Time {
 
 // NextRetrogradeToPrograde 下一次逆行转顺行留 / next station from retrograde to prograde.
 //
-// 返回 date 之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func NextRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextUranusRetrogradeToPrograde(jde), date.Location(), false)
@@ -279,8 +271,7 @@ func NextRetrogradeToPrograde(date time.Time) time.Time {
 
 // LastEasternQuadrature 上一次东方照 / previous eastern quadrature.
 //
-// 返回 date 之前最近一次东方照时刻，结果保持 date 的时区。
-// Returns the most recent eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次东方照时刻，结果保持 date 的时区。
 func LastEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastUranusEasternQuadrature(jde), date.Location(), false)
@@ -288,8 +279,7 @@ func LastEasternQuadrature(date time.Time) time.Time {
 
 // NextEasternQuadrature 下一次东方照 / next eastern quadrature.
 //
-// 返回 date 之后最近一次东方照时刻，结果保持 date 的时区。
-// Returns the next eastern quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次东方照时刻，结果保持 date 的时区。
 func NextEasternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextUranusEasternQuadrature(jde), date.Location(), false)
@@ -297,8 +287,7 @@ func NextEasternQuadrature(date time.Time) time.Time {
 
 // LastWesternQuadrature 上一次西方照 / previous western quadrature.
 //
-// 返回 date 之前最近一次西方照时刻，结果保持 date 的时区。
-// Returns the most recent western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次西方照时刻，结果保持 date 的时区。
 func LastWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastUranusWesternQuadrature(jde), date.Location(), false)
@@ -306,8 +295,7 @@ func LastWesternQuadrature(date time.Time) time.Time {
 
 // NextWesternQuadrature 下一次西方照 / next western quadrature.
 //
-// 返回 date 之后最近一次西方照时刻，结果保持 date 的时区。
-// Returns the next western quadrature relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次西方照时刻，结果保持 date 的时区。
 func NextWesternQuadrature(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextUranusWesternQuadrature(jde), date.Location(), false)

venus/transit.go

@@ -0,0 +1,73 @@
+package venus
+
+import (
+	"time"
+
+	"b612.me/astro/basic"
+)
+
+// TransitInfo 地心金星凌日信息 / geocentric Venus transit information.
+//
+// Start、Greatest、End、InternalStart、InternalEnd 都保持调用者输入的时区。
+// 内切接触不存在时 InternalStart / InternalEnd 为零值。
+// Start, Greatest, End, InternalStart, and InternalEnd preserve the caller's timezone.
+// InternalStart and InternalEnd are zero values when internal contacts do not exist.
+type TransitInfo struct {
+	Valid bool
+
+	Start         time.Time
+	InternalStart time.Time
+	Greatest      time.Time
+	InternalEnd   time.Time
+	End           time.Time
+
+	Duration         time.Duration
+	InternalDuration time.Duration
+
+	MinimumSeparationArcsec  float64
+	SunSemidiameterArcsec    float64
+	PlanetSemidiameterArcsec float64
+
+	HasInternal bool
+}
+
+// NextTransit 下一次地心金星凌日 / next geocentric Venus transit.
+func NextTransit(date time.Time) TransitInfo {
+	return transitInfoFromBasic(basic.NextVenusTransit(basic.Date2JDE(date.UTC())), date.Location())
+}
+
+// LastTransit 上一次地心金星凌日 / previous geocentric Venus transit.
+func LastTransit(date time.Time) TransitInfo {
+	return transitInfoFromBasic(basic.LastVenusTransit(basic.Date2JDE(date.UTC())), date.Location())
+}
+
+// ClosestTransit 最近一次地心金星凌日 / closest geocentric Venus transit.
+func ClosestTransit(date time.Time) TransitInfo {
+	return transitInfoFromBasic(basic.ClosestVenusTransit(basic.Date2JDE(date.UTC())), date.Location())
+}
+
+func transitInfoFromBasic(result basic.PlanetTransitResult, loc *time.Location) TransitInfo {
+	if !result.Valid {
+		return TransitInfo{}
+	}
+	start := basic.JDE2DateByZone(result.ExternalIngress, loc, false)
+	greatest := basic.JDE2DateByZone(result.Greatest, loc, false)
+	end := basic.JDE2DateByZone(result.ExternalEgress, loc, false)
+	info := TransitInfo{
+		Valid:                    true,
+		Start:                    start,
+		Greatest:                 greatest,
+		End:                      end,
+		Duration:                 end.Sub(start),
+		MinimumSeparationArcsec:  result.MinimumSeparationArcsec,
+		SunSemidiameterArcsec:    result.SunSemidiameterArcsec,
+		PlanetSemidiameterArcsec: result.PlanetSemidiameterArcsec,
+		HasInternal:              result.HasInternal,
+	}
+	if result.HasInternal {
+		info.InternalStart = basic.JDE2DateByZone(result.InternalIngress, loc, false)
+		info.InternalEnd = basic.JDE2DateByZone(result.InternalEgress, loc, false)
+		info.InternalDuration = info.InternalEnd.Sub(info.InternalStart)
+	}
+	return info
+}

venus/transit_test.go

@@ -0,0 +1,23 @@
+package venus
+
+import (
+	"testing"
+	"time"
+)
+
+func TestTransitWrappers(t *testing.T) {
+	loc := time.FixedZone("CST", 8*3600)
+	info := NextTransit(time.Date(2012, 1, 1, 0, 0, 0, 0, loc))
+	if !info.Valid {
+		t.Fatal("expected valid transit")
+	}
+	if info.Greatest.Location() != loc {
+		t.Fatalf("timezone mismatch: got %v want %v", info.Greatest.Location(), loc)
+	}
+	if info.Greatest.Year() != 2012 || info.Greatest.Month() != time.June || info.Greatest.Day() != 6 {
+		t.Fatalf("unexpected greatest time: %s", info.Greatest)
+	}
+	if !info.HasInternal || info.Duration <= 0 || info.InternalDuration <= 0 {
+		t.Fatalf("unexpected durations: %+v", info)
+	}
+}

venus/venus.go

@@ -207,8 +207,7 @@ func SetTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, er
 
 // LastConjunction 上一次合日 / previous conjunction with the Sun.
 //
-// 返回 date 之前最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the most recent conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次与太阳的合日时刻，结果保持 date 的时区。
 func LastConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.LastVenusConjunction(jde), date.Location(), false)
@@ -216,8 +215,7 @@ func LastConjunction(date time.Time) time.Time {
 
 // NextConjunction 下一次合日 / next conjunction with the Sun.
 //
-// 返回 date 之后最近一次与太阳的合日时刻，结果保持 date 的时区。
-// Returns the next conjunction with the Sun relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次与太阳的合日时刻，结果保持 date 的时区。
 func NextConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
 	return basic.JDE2DateByZone(basic.NextVenusConjunction(jde), date.Location(), false)
@@ -225,144 +223,128 @@ func NextConjunction(date time.Time) time.Time {
 
 // LastInferiorConjunction 上一次下合 / previous inferior conjunction.
 //
-// 返回 date 之前最近一次下合时刻，结果保持 date 的时区。
-// Returns the most recent inferior conjunction relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次下合时刻，结果保持 date 的时区。
 func LastInferiorConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastVenusInferiorConjunction(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastVenusInferiorConjunctionInclusive(jde), date.Location(), false)
 }
 
 // NextInferiorConjunction 下一次下合 / next inferior conjunction.
 //
-// 返回 date 之后最近一次下合时刻，结果保持 date 的时区。
-// Returns the next inferior conjunction relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次下合时刻，结果保持 date 的时区。
 func NextInferiorConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextVenusInferiorConjunction(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextVenusInferiorConjunctionInclusive(jde), date.Location(), false)
 }
 
 // LastSuperiorConjunction 上一次上合 / previous superior conjunction.
 //
-// 返回 date 之前最近一次上合时刻，结果保持 date 的时区。
-// Returns the most recent superior conjunction relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次上合时刻，结果保持 date 的时区。
 func LastSuperiorConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastVenusSuperiorConjunction(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastVenusSuperiorConjunctionInclusive(jde), date.Location(), false)
 }
 
 // NextSuperiorConjunction 下一次上合 / next superior conjunction.
 //
-// 返回 date 之后最近一次上合时刻，结果保持 date 的时区。
-// Returns the next superior conjunction relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次上合时刻，结果保持 date 的时区。
 func NextSuperiorConjunction(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextVenusSuperiorConjunction(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextVenusSuperiorConjunctionInclusive(jde), date.Location(), false)
 }
 
 // LastRetrograde 上一次留 / previous stationary point.
 //
-// 返回 date 之前最近一次留时刻，不区分顺转逆还是逆转顺，结果保持 date 的时区。
-// Returns the most recent stationary point relative to date without distinguishing direction, keeping date's time zone.
+// 返回 date 当前或之前最近一次留时刻，不区分顺转逆还是逆转顺，结果保持 date 的时区。
 func LastRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastVenusRetrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastVenusRetrogradeInclusive(jde), date.Location(), false)
 }
 
 // NextRetrograde 下一次留 / next stationary point.
 //
-// 返回 date 之后最近一次留时刻，不区分顺转逆还是逆转顺，结果保持 date 的时区。
-// Returns the next stationary point relative to date without distinguishing direction, keeping date's time zone.
+// 返回 date 当前或之后最近一次留时刻，不区分顺转逆还是逆转顺，结果保持 date 的时区。
 func NextRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextVenusRetrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextVenusRetrogradeInclusive(jde), date.Location(), false)
 }
 
 // LastProgradeToRetrograde 上一次顺行转逆行留 / previous station from prograde to retrograde.
 //
-// 返回 date 之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func LastProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastVenusProgradeToRetrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastVenusProgradeToRetrogradeInclusive(jde), date.Location(), false)
 }
 
 // NextProgradeToRetrograde 下一次顺行转逆行留 / next station from prograde to retrograde.
 //
-// 返回 date 之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from prograde to retrograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由顺行转为逆行的留时刻，结果保持 date 的时区。
 func NextProgradeToRetrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextVenusProgradeToRetrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextVenusProgradeToRetrogradeInclusive(jde), date.Location(), false)
 }
 
 // LastRetrogradeToPrograde 上一次逆行转顺行留 / previous station from retrograde to prograde.
 //
-// 返回 date 之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the most recent stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func LastRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastVenusRetrogradeToPrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastVenusRetrogradeToProgradeInclusive(jde), date.Location(), false)
 }
 
 // NextRetrogradeToPrograde 下一次逆行转顺行留 / next station from retrograde to prograde.
 //
-// 返回 date 之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
-// Returns the next stationary point where motion changes from retrograde to prograde relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次由逆行转为顺行的留时刻，结果保持 date 的时区。
 func NextRetrogradeToPrograde(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextVenusRetrogradeToPrograde(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextVenusRetrogradeToProgradeInclusive(jde), date.Location(), false)
 }
 
 // LastGreatestElongation 上一次大距 / previous greatest elongation.
 //
-// 返回 date 之前最近一次大距时刻，不区分东西大距，结果保持 date 的时区。
-// Returns the most recent greatest elongation relative to date without distinguishing east or west, keeping date's time zone.
+// 返回 date 当前或之前最近一次大距时刻，不区分东西大距，结果保持 date 的时区。
 func LastGreatestElongation(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastVenusGreatestElongation(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastVenusGreatestElongationInclusive(jde), date.Location(), false)
 }
 
 // NextGreatestElongation 下一次大距 / next greatest elongation.
 //
-// 返回 date 之后最近一次大距时刻，不区分东西大距，结果保持 date 的时区。
-// Returns the next greatest elongation relative to date without distinguishing east or west, keeping date's time zone.
+// 返回 date 当前或之后最近一次大距时刻，不区分东西大距，结果保持 date 的时区。
 func NextGreatestElongation(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextVenusGreatestElongation(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextVenusGreatestElongationInclusive(jde), date.Location(), false)
 }
 
 // LastGreatestElongationEast 上一次东大距 / previous greatest eastern elongation.
 //
-// 返回 date 之前最近一次东大距时刻，结果保持 date 的时区。
-// Returns the most recent greatest eastern elongation relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次东大距时刻，结果保持 date 的时区。
 func LastGreatestElongationEast(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastVenusGreatestElongationEast(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastVenusGreatestElongationEastInclusive(jde), date.Location(), false)
 }
 
 // NextGreatestElongationEast 下一次东大距 / next greatest eastern elongation.
 //
-// 返回 date 之后最近一次东大距时刻，结果保持 date 的时区。
-// Returns the next greatest eastern elongation relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次东大距时刻，结果保持 date 的时区。
 func NextGreatestElongationEast(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextVenusGreatestElongationEast(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextVenusGreatestElongationEastInclusive(jde), date.Location(), false)
 }
 
 // LastGreatestElongationWest 上一次西大距 / previous greatest western elongation.
 //
-// 返回 date 之前最近一次西大距时刻，结果保持 date 的时区。
-// Returns the most recent greatest western elongation relative to date, keeping date's time zone.
+// 返回 date 当前或之前最近一次西大距时刻，结果保持 date 的时区。
 func LastGreatestElongationWest(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.LastVenusGreatestElongationWest(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.LastVenusGreatestElongationWestInclusive(jde), date.Location(), false)
 }
 
 // NextGreatestElongationWest 下一次西大距 / next greatest western elongation.
 //
-// 返回 date 之后最近一次西大距时刻，结果保持 date 的时区。
-// Returns the next greatest western elongation relative to date, keeping date's time zone.
+// 返回 date 当前或之后最近一次西大距时刻，结果保持 date 的时区。
 func NextGreatestElongationWest(date time.Time) time.Time {
 	jde := basic.TD2UT(basic.Date2JDE(date.UTC()), true)
-	return basic.JDE2DateByZone(basic.NextVenusGreatestElongationWest(jde), date.Location(), false)
+	return basic.JDE2DateByZone(basic.NextVenusGreatestElongationWestInclusive(jde), date.Location(), false)
 }