feat: 完善时标与天象几何计算并扩展输出接口

- 新增时标、ΔT 模型、质心时间与 UT1 支持
- 改进日月食、月掩、行星事件及路径边界计算
- 完善恒星三维自行与动态距离传播
- 扩展 SVG、GeoJSON、KML 输出与底层距离换算工具
- 整理中英文手册、示例资源及回归测试

lite/internal/common.go

@@ -5,6 +5,8 @@ import (
 	"math"
 
 	. "b612.me/astro/tools"
+
+	"b612.me/astro/basic"
 )
 
 const (
@@ -17,8 +19,8 @@ var (
 	ErrNotOnThisDate = errors.New("rise/set event occurs on adjacent date")
 )
 
-func MeanObliquity(jd float64) float64 {
-	t := (jd - 2451545.0) / 36525.0
+func MeanObliquity(jde float64) float64 {
+	t := (jde - 2451545.0) / 36525.0
 	return 23.4392911111 - (46.8150*t+0.00059*t*t-0.001813*t*t*t)/3600.0
 }
 
@@ -27,8 +29,8 @@ func MeanSiderealTime(jd float64) float64 {
 	return Limit360(280.46061837 + 360.98564736629*(jd-2451545.0) + 0.000387933*t*t - t*t*t/38710000.0)
 }
 
-func EclipticToEquatorial(jd, lo, bo float64) (float64, float64) {
-	eps := MeanObliquity(jd)
+func EclipticToEquatorial(jde, lo, bo float64) (float64, float64) {
+	eps := MeanObliquity(jde)
 	ra := math.Atan2(Sin(lo)*Cos(eps)-Tan(bo)*Sin(eps), Cos(lo)) * 180.0 / math.Pi
 	if ra < 0 {
 		ra += 360
@@ -38,7 +40,7 @@ func EclipticToEquatorial(jd, lo, bo float64) (float64, float64) {
 }
 
 func HorizontalCoordinates(ra, dec, jd, lon, lat float64) (float64, float64, float64) {
-	lst := Limit360(MeanSiderealTime(jd) + lon)
+	lst := Limit360(MeanSiderealTime(basic.UTC2UT1(jd)) + lon)
 	hourAngle := Limit360(lst - ra)
 	altitude := ArcSin(clampUnit(Sin(lat)*Sin(dec) + Cos(lat)*Cos(dec)*Cos(hourAngle)))
 
@@ -63,7 +65,7 @@ func TopocentricRaDec(ra, dec, observerLat, observerLon, jd, distanceEarthRadii,
 	rhoCos := math.Cos(u) + heightMeters/6378140.0*Cos(observerLat)
 	parallax := math.Asin(1.0 / distanceEarthRadii)
 
-	hourAngle := (Limit360(MeanSiderealTime(jd) + observerLon - ra)) * math.Pi / 180.0
+	hourAngle := (Limit360(MeanSiderealTime(basic.UTC2UT1(jd)) + observerLon - ra)) * math.Pi / 180.0
 	decRad := dec * math.Pi / 180.0
 
 	numerator := -rhoCos * math.Sin(parallax) * math.Sin(hourAngle)

lite/internal/sun.go

@@ -2,47 +2,48 @@ package internal
 
 import . "b612.me/astro/tools"
 
-func SunLo(jd float64) float64 {
-	t := (jd - 2451545.0) / 365250.0
+func SunLo(jde float64) float64 {
+	t := (jde - 2451545.0) / 365250.0
 	return Limit360(280.4664567 + 360007.6982779*t + 0.03032028*t*t + t*t*t/49931.0 - t*t*t*t/15299.0 - t*t*t*t*t/1988000.0)
 }
 
-func SunMeanAnomaly(jd float64) float64 {
-	t := (jd - 2451545.0) / 36525.0
+func SunMeanAnomaly(jde float64) float64 {
+	t := (jde - 2451545.0) / 36525.0
 	return Limit360(357.5291092 + 35999.0502909*t - 0.0001559*t*t - 0.00000048*t*t*t)
 }
 
-func EarthEccentricity(jd float64) float64 {
-	t := (jd - 2451545.0) / 36525.0
+func EarthEccentricity(jde float64) float64 {
+	t := (jde - 2451545.0) / 36525.0
 	return 0.016708617 - 0.000042037*t - 0.0000001236*t*t
 }
 
-func SunCenter(jd float64) float64 {
-	t := (jd - 2451545.0) / 36525.0
-	m := SunMeanAnomaly(jd)
+func SunCenter(jde float64) float64 {
+	t := (jde - 2451545.0) / 36525.0
+	m := SunMeanAnomaly(jde)
 	return (1.9146-0.004817*t-0.000014*t*t)*Sin(m) + (0.019993-0.000101*t)*Sin(2*m) + 0.00029*Sin(3*m)
 }
 
-func SunTrueLo(jd float64) float64 {
-	return Limit360(SunLo(jd) + SunCenter(jd))
+// 本文件以 jde（力学时儒略日）键控；lite 包装层的实参是 UTC 民用 JD，69 s 的历元差远低于轻量公式精度。
+func SunTrueLo(jde float64) float64 {
+	return Limit360(SunLo(jde) + SunCenter(jde))
 }
 
-func SunApparentLo(jd float64) float64 {
-	t := (jd - 2451545.0) / 36525.0
-	return Limit360(SunTrueLo(jd) - 0.00569 - 0.00478*Sin(125.04-1934.136*t))
+func SunApparentLo(jde float64) float64 {
+	t := (jde - 2451545.0) / 36525.0
+	return Limit360(SunTrueLo(jde) - 0.00569 - 0.00478*Sin(125.04-1934.136*t))
 }
 
-func SunDistanceAU(jd float64) float64 {
-	c := SunCenter(jd)
-	m := SunMeanAnomaly(jd)
-	e := EarthEccentricity(jd)
+func SunDistanceAU(jde float64) float64 {
+	c := SunCenter(jde)
+	m := SunMeanAnomaly(jde)
+	e := EarthEccentricity(jde)
 	return 1.000001018 * (1 - e*e) / (1 + e*Cos(m+c))
 }
 
-func SunTrueRaDec(jd float64) (float64, float64) {
-	return EclipticToEquatorial(jd, SunTrueLo(jd), 0)
+func SunTrueRaDec(jde float64) (float64, float64) {
+	return EclipticToEquatorial(jde, SunTrueLo(jde), 0)
 }
 
-func SunApparentRaDec(jd float64) (float64, float64) {
-	return EclipticToEquatorial(jd, SunApparentLo(jd), 0)
+func SunApparentRaDec(jde float64) (float64, float64) {
+	return EclipticToEquatorial(jde, SunApparentLo(jde), 0)
 }