Files
astro/basic/saturn_events.go
T
b612 044f2f4381 feat: 引入可切换星历模型并扩展天象观测链路
- 新增半解析、旧模型、自定义与多源堆叠星历实例,提供 Context、Instance、SPK 读取及状态与视位置计算
- 统一太阳、月球和行星实例接口,扩展黄经穿越、留、相位、最近角距、偕日可见、任意高度升落、轨道节点及凌日等天象查询
- 完善日月食、月掩与凌日的月缘剖面、有限盘面接触、站心修正、局地可见性、全球路径和地图输出
- 新增 SVG、GeoJSON、KML 天象输出及凌日、月掩和月缘地形相关缓存与几何求解
- 新增恒星星表导入与查询,支持 CSV、Hipparcos、BSC5、Stellarium 等格式及名称、交叉标识、锥面检索和星等过滤
- 补充 IAU 2006、地球定向、折射消光、大气观测、轨道传播及半解析行星/月球数据支持
- 将默认未来民用时标切换为 TimeScaleLeapHour,更新 2027–2400 农历速查表、中文日期解析和时区边界处理
- 增加事件基线、跨模型回归、几何边界、月缘地形和输出契约测试,完善中英文手册、示例资源、NOTICE 与忽略规则
2026-10-15 23:54:15 +08:00

326 lines
12 KiB
Go

package basic
import (
"math"
. "b612.me/astro/tools"
)
// Pos
const (
SATURN_S_PERIOD = 1 / ((1 / 365.256363004) - (1 / 10759.0))
saturnEventSearchN = 16
saturnPhaseCoarseTolerance = 30.0 / 86400.0
)
func saturnSunLongitudeDelta(jde, degree float64, filter bool, instances ...*Instance) float64 {
inst := instanceValue(instances)
sub := Limit360(Limit360(SaturnApparentLoWithInstance(jde, inst)-HSunApparentLoWithInstance(jde, inst)) - degree)
if filter {
if sub > 180 {
sub -= 360
}
if sub < -180 {
sub += 360
}
}
return sub
}
func saturnSunLongitudeDeltaN(jde, degree float64, filter bool, n int, instances ...*Instance) float64 {
inst := instanceValue(instances)
sub := Limit360(Limit360(SaturnApparentLoNWithInstance(jde, n, inst)-HSunApparentLoNWithInstance(jde, n, inst)) - degree)
if filter {
if sub > 180 {
sub -= 360
}
if sub < -180 {
sub += 360
}
}
return sub
}
func saturnRADerivative(jde, delta float64, instances ...*Instance) float64 {
inst := instanceValue(instances)
sub := SaturnApparentRaWithInstance(jde+delta, inst) - SaturnApparentRaWithInstance(jde-delta, inst)
if sub > 180 {
sub -= 360
}
if sub < -180 {
sub += 360
}
return sub / (2 * delta)
}
func saturnRADerivativeN(jde, delta float64, n int, instances ...*Instance) float64 {
inst := instanceValue(instances)
sub := SaturnApparentRaNWithInstance(jde+delta, n, inst) - SaturnApparentRaNWithInstance(jde-delta, n, inst)
if sub > 180 {
sub -= 360
}
if sub < -180 {
sub += 360
}
return sub / (2 * delta)
}
func saturnConjunctionFull(jde, degree float64, next uint8, instances ...*Instance) float64 {
inst := instanceValue(instances)
//0=last 1=next
if !isFiniteFloat(jde) || !isFiniteFloat(degree) {
return math.NaN()
}
daysPerDegree := SATURN_S_PERIOD / 360
currentDelta := saturnSunLongitudeDelta(jde, degree, false, inst)
if next == 0 {
jde -= (360 - currentDelta) * daysPerDegree
} else {
jde += daysPerDegree * currentDelta
}
estimateJDE := jde
converged := false
for i := 0; i < eventNewtonMaxIterations; i++ {
prevJDE := estimateJDE
longitudeDelta := saturnSunLongitudeDelta(prevJDE, degree, true, inst)
longitudeSlope := (saturnSunLongitudeDelta(prevJDE+0.000005, degree, true, inst) - saturnSunLongitudeDelta(prevJDE-0.000005, degree, true, inst)) / 0.00001
nextJD := prevJDE - longitudeDelta/longitudeSlope
estimateJDE = nextJD
if math.Abs(nextJD-prevJDE) <= 0.00001 {
converged = true
break
}
}
if !converged {
return math.NaN()
}
return TT2UTC(estimateJDE)
}
func saturnConjunction(jde, degree float64, next uint8, instances ...*Instance) float64 {
inst := instanceValue(instances)
//0=last 1=next
if !isFiniteFloat(jde) || !isFiniteFloat(degree) {
return math.NaN()
}
daysPerDegree := SATURN_S_PERIOD / 360
currentDelta := saturnSunLongitudeDelta(jde, degree, false, inst)
if next == 0 {
jde -= (360 - currentDelta) * daysPerDegree
} else {
jde += daysPerDegree * currentDelta
}
estimateJDE := jde
converged := false
for i := 0; i < eventNewtonMaxIterations; i++ {
prevJDE := estimateJDE
longitudeDelta := saturnSunLongitudeDeltaN(prevJDE, degree, true, saturnEventSearchN, inst)
longitudeSlope := (saturnSunLongitudeDeltaN(prevJDE+0.000005, degree, true, saturnEventSearchN, inst) - saturnSunLongitudeDeltaN(prevJDE-0.000005, degree, true, saturnEventSearchN, inst)) / 0.00001
nextJD := prevJDE - longitudeDelta/longitudeSlope
estimateJDE = nextJD
if math.Abs(nextJD-prevJDE) <= saturnPhaseCoarseTolerance {
converged = true
break
}
}
if !converged {
return math.NaN()
}
converged = false
for i := 0; i < eventNewtonMaxIterations; i++ {
prevJDE := estimateJDE
longitudeDelta := saturnSunLongitudeDelta(prevJDE, degree, true, inst)
longitudeSlope := (saturnSunLongitudeDelta(prevJDE+0.000005, degree, true, inst) - saturnSunLongitudeDelta(prevJDE-0.000005, degree, true, inst)) / 0.00001
nextJD := prevJDE - longitudeDelta/longitudeSlope
estimateJDE = nextJD
if math.Abs(nextJD-prevJDE) <= 0.00001 {
converged = true
break
}
}
if !converged {
return math.NaN()
}
return TT2UTC(estimateJDE)
}
// LastSaturnConjunctionWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func LastSaturnConjunctionWithInstance(jde float64, inst *Instance) float64 {
return inclusiveLastPhaseEvent(jde, 0, func(jde, degree float64, next uint8) float64 {
return saturnConjunction(jde, degree, next, inst)
})
}
// NextSaturnConjunctionWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func NextSaturnConjunctionWithInstance(jde float64, inst *Instance) float64 {
return inclusiveNextPhaseEvent(jde, 0, func(jde, degree float64, next uint8) float64 {
return saturnConjunction(jde, degree, next, inst)
})
}
// LastSaturnOppositionWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func LastSaturnOppositionWithInstance(jde float64, inst *Instance) float64 {
return inclusiveLastPhaseEvent(jde, 180, func(jde, degree float64, next uint8) float64 {
return saturnConjunction(jde, degree, next, inst)
})
}
// NextSaturnOppositionWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func NextSaturnOppositionWithInstance(jde float64, inst *Instance) float64 {
return inclusiveNextPhaseEvent(jde, 180, func(jde, degree float64, next uint8) float64 {
return saturnConjunction(jde, degree, next, inst)
})
}
// NextSaturnEasternQuadratureWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func NextSaturnEasternQuadratureWithInstance(jde float64, inst *Instance) float64 {
return inclusiveNextPhaseEvent(jde, 90, func(jde, degree float64, next uint8) float64 {
return saturnConjunction(jde, degree, next, inst)
})
}
// LastSaturnEasternQuadratureWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func LastSaturnEasternQuadratureWithInstance(jde float64, inst *Instance) float64 {
return inclusiveLastPhaseEvent(jde, 90, func(jde, degree float64, next uint8) float64 {
return saturnConjunction(jde, degree, next, inst)
})
}
// NextSaturnWesternQuadratureWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func NextSaturnWesternQuadratureWithInstance(jde float64, inst *Instance) float64 {
return inclusiveNextPhaseEvent(jde, 270, func(jde, degree float64, next uint8) float64 {
return saturnConjunction(jde, degree, next, inst)
})
}
// LastSaturnWesternQuadratureWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func LastSaturnWesternQuadratureWithInstance(jde float64, inst *Instance) float64 {
return inclusiveLastPhaseEvent(jde, 270, func(jde, degree float64, next uint8) float64 {
return saturnConjunction(jde, degree, next, inst)
})
}
func saturnRetrogradeAroundOpposition(oppositionJD float64, searchBeforeOpposition bool, instances ...*Instance) float64 {
inst := instanceValue(instances)
if !isFiniteFloat(oppositionJD) {
return math.NaN()
}
oppositionTT := UTC2TT(oppositionJD)
startTT := oppositionTT
endTT := oppositionTT
if searchBeforeOpposition {
easternQuadratureUT := saturnConjunction(oppositionTT, 90, 0, inst)
startTT = UTC2TT(easternQuadratureUT)
} else {
westernQuadratureUT := saturnConjunction(oppositionTT, 270, 1, inst)
endTT = UTC2TT(westernQuadratureUT)
}
bestJDE := zeroEventInWindow(startTT, endTT, 2.0, 2.0, 30.0/86400.0, func(jd float64) float64 {
return saturnRADerivativeN(jd, stationDerivativeStepDay, saturnEventSearchN, inst)
}, func(jd float64) float64 {
return saturnRADerivative(jd, stationDerivativeStepDay, inst)
})
return TT2UTC(bestJDE)
}
// NextSaturnRetrogradeToProgradeWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func NextSaturnRetrogradeToProgradeWithInstance(jde float64, inst *Instance) float64 {
if !isFiniteFloat(jde) {
return math.NaN()
}
lastOppositionJD := saturnConjunctionFull(jde, 180, 0, inst)
date := saturnRetrogradeAroundOpposition(lastOppositionJD, false, inst)
if isFiniteFloat(date) && stationUTQueryAfterOrEqual(date, jde) {
return date
}
nextOppositionJD := saturnConjunctionFull(jde, 180, 1, inst)
if !isFiniteFloat(nextOppositionJD) {
return math.NaN()
}
date = saturnRetrogradeAroundOpposition(nextOppositionJD, false, inst)
if !isFiniteFloat(date) || !stationUTQueryAfterOrEqual(date, jde) {
return math.NaN()
}
return date
}
// LastSaturnRetrogradeToProgradeWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func LastSaturnRetrogradeToProgradeWithInstance(jde float64, inst *Instance) float64 {
if !isFiniteFloat(jde) {
return math.NaN()
}
lastOppositionJD := saturnConjunctionFull(jde, 180, 0, inst)
date := saturnRetrogradeAroundOpposition(lastOppositionJD, false, inst)
if isFiniteFloat(date) && stationUTQueryBeforeOrEqual(date, jde) {
return date
}
if !isFiniteFloat(lastOppositionJD) {
return math.NaN()
}
previousOppositionJD := saturnConjunctionFull(eventUTLastQueryTT(lastOppositionJD), 180, 0, inst)
if !isFiniteFloat(previousOppositionJD) {
return math.NaN()
}
date = saturnRetrogradeAroundOpposition(previousOppositionJD, false, inst)
if !isFiniteFloat(date) || !stationUTQueryBeforeOrEqual(date, jde) {
return math.NaN()
}
return date
}
// NextSaturnProgradeToRetrogradeWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func NextSaturnProgradeToRetrogradeWithInstance(jde float64, inst *Instance) float64 {
if !isFiniteFloat(jde) {
return math.NaN()
}
nextOppositionJD := saturnConjunctionFull(jde, 180, 1, inst)
date := saturnRetrogradeAroundOpposition(nextOppositionJD, true, inst)
if isFiniteFloat(date) && stationUTQueryAfterOrEqual(date, jde) {
return date
}
if !isFiniteFloat(nextOppositionJD) {
return math.NaN()
}
followingOppositionJD := saturnConjunctionFull(eventUTNextQueryTT(nextOppositionJD), 180, 1, inst)
if !isFiniteFloat(followingOppositionJD) {
return math.NaN()
}
date = saturnRetrogradeAroundOpposition(followingOppositionJD, true, inst)
if !isFiniteFloat(date) || !stationUTQueryAfterOrEqual(date, jde) {
return math.NaN()
}
return date
}
// LastSaturnProgradeToRetrogradeWithInstance 用指定星历实例求值;inst 为 nil 时用进程当前模型 / evaluation with an explicit instance; nil uses the process model.
func LastSaturnProgradeToRetrogradeWithInstance(jde float64, inst *Instance) float64 {
if !isFiniteFloat(jde) {
return math.NaN()
}
nextOppositionJD := saturnConjunctionFull(jde, 180, 1, inst)
date := saturnRetrogradeAroundOpposition(nextOppositionJD, true, inst)
if isFiniteFloat(date) && stationUTQueryBeforeOrEqual(date, jde) {
return date
}
if !isFiniteFloat(nextOppositionJD) {
return math.NaN()
}
lastOppositionJD := saturnConjunctionFull(jde, 180, 0, inst)
if !isFiniteFloat(lastOppositionJD) {
return math.NaN()
}
date = saturnRetrogradeAroundOpposition(lastOppositionJD, true, inst)
if !isFiniteFloat(date) || !stationUTQueryBeforeOrEqual(date, jde) {
return math.NaN()
}
return date
}