feat: 扩展天文计算能力

- 新增日食、月食、本地可见性、中心线、半影区域、SVG 图示与沙罗周期信息 - 新增行星冲合、留、方照、物理星历、视直径、相位、亮肢角、轨道节点等计算 - 新增木星伽利略卫星位置、现象与接触事件计算 - 新增恒星星表、星座判定、自行修正与观测辅助能力 - 新增 coord、formula、orbit、sundial、lite/sun、lite/moon 等扩展包 - 完善农历年号、月相英文别名、视差角、大气质量、折射、日晷与双星计算 - 增加 NASA、JPL Horizons、IMCCE 等回归测试数据与基线测试 - 重构基础算法文件组织，补充大量公开 API 注释和语义回归测试 - 更新中文和英文 README，补充示例、精度说明、SVG 配图
2026-05-01 22:38:44 +08:00
parent 98ff574495
commit 3ffdbe0034
365 changed files with 63589 additions and 17508 deletions
@@ -0,0 +1,125 @@
+package internal
+
+import (
+	"math"
+
+	. "b612.me/astro/tools"
+)
+
+type MoonState struct {
+	Longitude          float64
+	Latitude           float64
+	DistanceEarthRadii float64
+	RightAscension     float64
+	Declination        float64
+}
+
+func MoonGeocentric(jd float64) MoonState {
+	d := jd - 2451543.5
+
+	node := Limit360(125.1228 - 0.0529538083*d)
+	inclination := 5.1454
+	perigee := Limit360(318.0634 + 0.1643573223*d)
+	semiMajorAxis := 60.2666
+	eccentricity := 0.054900
+	meanAnomaly := Limit360(115.3654 + 13.0649929509*d)
+	meanLongitude := Limit360(node + perigee + meanAnomaly)
+	argumentLatitude := Limit360(meanLongitude - node)
+
+	sunPerigee := Limit360(282.9404 + 0.0000470935*d)
+	sunEccentricity := 0.016709 - 0.000000001151*d
+	sunMeanAnomaly := Limit360(356.0470 + 0.9856002585*d)
+	sunTrueLongitude, _ := orbitalLongitudeDistance(sunPerigee, sunEccentricity, 1, sunMeanAnomaly)
+
+	longitude, latitude, distance := orbitalLongitudeLatitudeDistance(node, inclination, perigee, semiMajorAxis, eccentricity, meanAnomaly)
+	elongation := Limit360(meanLongitude - sunTrueLongitude)
+
+	longitude += -1.274 * Sin(meanAnomaly-2*elongation)
+	longitude += 0.658 * Sin(2*elongation)
+	longitude += -0.186 * Sin(sunMeanAnomaly)
+	longitude += -0.059 * Sin(2*meanAnomaly-2*elongation)
+	longitude += -0.057 * Sin(meanAnomaly-2*elongation+sunMeanAnomaly)
+	longitude += 0.053 * Sin(meanAnomaly+2*elongation)
+	longitude += 0.046 * Sin(2*elongation-sunMeanAnomaly)
+	longitude += 0.041 * Sin(meanAnomaly-sunMeanAnomaly)
+	longitude += -0.035 * Sin(elongation)
+	longitude += -0.031 * Sin(meanAnomaly+sunMeanAnomaly)
+	longitude += -0.015 * Sin(2*argumentLatitude-2*elongation)
+	longitude += 0.011 * Sin(meanAnomaly-4*elongation)
+
+	latitude += -0.173 * Sin(argumentLatitude-2*elongation)
+	latitude += -0.055 * Sin(meanAnomaly-argumentLatitude-2*elongation)
+	latitude += -0.046 * Sin(meanAnomaly+argumentLatitude-2*elongation)
+	latitude += 0.033 * Sin(argumentLatitude+2*elongation)
+	latitude += 0.017 * Sin(2*meanAnomaly+argumentLatitude)
+
+	distance += -0.58 * Cos(meanAnomaly-2*elongation)
+	distance += -0.46 * Cos(2*elongation)
+
+	longitude = Limit360(longitude)
+	ra, dec := EclipticToEquatorial(jd, longitude, latitude)
+	return MoonState{
+		Longitude:          longitude,
+		Latitude:           latitude,
+		DistanceEarthRadii: distance,
+		RightAscension:     ra,
+		Declination:        dec,
+	}
+}
+
+func MoonTopocentric(jd, observerLon, observerLat, heightMeters float64) MoonState {
+	geo := MoonGeocentric(jd)
+	ra, dec := TopocentricRaDec(geo.RightAscension, geoDeclinationClamp(geo.Declination), observerLat, observerLon, jd, geo.DistanceEarthRadii, heightMeters)
+	geo.RightAscension = ra
+	geo.Declination = dec
+	return geo
+}
+
+func orbitalLongitudeLatitudeDistance(node, inclination, perigee, axis, eccentricity, meanAnomaly float64) (float64, float64, float64) {
+	meanAnomalyRad := meanAnomaly * math.Pi / 180.0
+	eccentricAnomaly := meanAnomalyRad + eccentricity*math.Sin(meanAnomalyRad)*(1+eccentricity*math.Cos(meanAnomalyRad))
+	for i := 0; i < 5; i++ {
+		eccentricAnomaly -= (eccentricAnomaly - eccentricity*math.Sin(eccentricAnomaly) - meanAnomalyRad) / (1 - eccentricity*math.Cos(eccentricAnomaly))
+	}
+
+	xv := axis * (math.Cos(eccentricAnomaly) - eccentricity)
+	yv := axis * math.Sqrt(1-eccentricity*eccentricity) * math.Sin(eccentricAnomaly)
+	trueAnomaly := math.Atan2(yv, xv)
+	radius := math.Hypot(xv, yv)
+
+	nodeRad := node * math.Pi / 180.0
+	inclinationRad := inclination * math.Pi / 180.0
+	perigeeRad := perigee * math.Pi / 180.0
+
+	xh := radius * (math.Cos(nodeRad)*math.Cos(trueAnomaly+perigeeRad) - math.Sin(nodeRad)*math.Sin(trueAnomaly+perigeeRad)*math.Cos(inclinationRad))
+	yh := radius * (math.Sin(nodeRad)*math.Cos(trueAnomaly+perigeeRad) + math.Cos(nodeRad)*math.Sin(trueAnomaly+perigeeRad)*math.Cos(inclinationRad))
+	zh := radius * math.Sin(trueAnomaly+perigeeRad) * math.Sin(inclinationRad)
+
+	longitude := math.Atan2(yh, xh) * 180.0 / math.Pi
+	latitude := math.Atan2(zh, math.Hypot(xh, yh)) * 180.0 / math.Pi
+	return Limit360(longitude), latitude, radius
+}
+
+func orbitalLongitudeDistance(perigee, eccentricity, axis, meanAnomaly float64) (float64, float64) {
+	meanAnomalyRad := meanAnomaly * math.Pi / 180.0
+	eccentricAnomaly := meanAnomalyRad + eccentricity*math.Sin(meanAnomalyRad)*(1+eccentricity*math.Cos(meanAnomalyRad))
+	for i := 0; i < 5; i++ {
+		eccentricAnomaly -= (eccentricAnomaly - eccentricity*math.Sin(eccentricAnomaly) - meanAnomalyRad) / (1 - eccentricity*math.Cos(eccentricAnomaly))
+	}
+
+	xv := axis * (math.Cos(eccentricAnomaly) - eccentricity)
+	yv := axis * math.Sqrt(1-eccentricity*eccentricity) * math.Sin(eccentricAnomaly)
+	trueAnomaly := math.Atan2(yv, xv) * 180.0 / math.Pi
+	radius := math.Hypot(xv, yv)
+	return Limit360(trueAnomaly + perigee), radius
+}
+
+func geoDeclinationClamp(dec float64) float64 {
+	if dec > 90 {
+		return 90
+	}
+	if dec < -90 {
+		return -90
+	}
+	return dec
+}