Files
astro/basic/planet_apparent.go
T
b612 2bf8478639 feat: 完善日月食与月掩几何链路并扩展历法接口
- 新增日月食中心带、偏食带、阴影足迹、等时线、食分线及升落边界计算,支持极区与混合食拓扑
- 新增日食单时刻阴影求解器、站心状态查询、批量采样和 ΔT 覆盖接口
- 重构恒星与行星月掩路径,补充有限盘面接触、站心修正、掩带宽度、极区投影及升落边界
- 扩展 SVG 与 GeoJSON 输出,支持详细面板、全球/极区/地球投影、边界闭合、时间标记和拓扑签名
- 扩展日月食候选搜索、局地搜索、沙罗序列预计算与范围外推,补充系列锚点和成员一致性校验
- 补齐古历纪年、儒略历独有闰日、多公历候选、历法改革跨日及精确日期运算接口
- 优化 ΔT、章动、恒星时、月球地平线、事件根搜索和本地星历缓存,降低重复计算开销并提升边界稳定
2026-09-17 12:27:40 +08:00

95 lines
3.2 KiB
Go

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) {
geo, tau, _ := planetApparentGeocentricPositionAndDistanceN(planetIndex, jd, n)
return geo, tau
}
func planetApparentGeocentricPositionAndDistanceN(
planetIndex int,
jd float64,
n int,
) (planetGeocentricPosition, float64, float64) {
ex, ey, ez := earthHeliocentricXYZN(jd, n)
geoNow := planetGeocentricPositionWithEarthN(planetIndex, jd, ex, ey, ez, n)
distance := math.Sqrt(geoNow.x*geoNow.x + geoNow.y*geoNow.y + geoNow.z*geoNow.z)
tau := 0.0057755183 * distance
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, distance
}
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)
}