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

basic/moon_horizon.go

@@ -1,58 +1,15 @@
 package basic
 
-import "math"
-
-// MoonHorizon 返回 UT 儒略日下海平面几何月球中心地平圈（月球恰好在地平线上的观测者轨迹，
+// MoonHorizon 返回 UTC 儒略日下海平面几何月球中心地平圈（月球恰好在地平线上的观测者轨迹，
 // 即月下点周围的地平圈）的 [经度, 纬度] 顶点，单位为度，不重复首点。视差与椭球口径同
 // HMoonHeight，不含折射；与 HMoonHeight(经, 纬, ..., 0) 配合时该圈上的点高度角为 0。
 // samples<=0 取 360，其余夹到 [12, 1440]。
-// MoonHorizon returns sea-level geometric Moon-centre horizon vertices in degrees for a UT Julian
+// MoonHorizon returns sea-level geometric Moon-centre horizon vertices in degrees for a UTC Julian
 // day: the locus of observers that see the Moon exactly on the horizon. Parallax and the observer
 // ellipsoid match HMoonHeight; refraction is excluded.
-func MoonHorizon(jdUT float64, samples int) [][2]float64 {
-	if !finite(jdUT) {
+func MoonHorizon(jdUTC float64, samples int) [][2]float64 {
+	if !finite(jdUTC) {
 		return nil
 	}
-	if samples <= 0 {
-		samples = 360
-	}
-	if samples < 12 {
-		samples = 12
-	} else if samples > 1440 {
-		samples = 1440
-	}
-	tt := TD2UT(jdUT, true)
-	ra, dec := HMoonTrueRaDec(tt)
-	distanceAU := HMoonAway(tt) / angularDiameterAstronomicalUnitKM
-	parallax := math.Sin(0.0024427777777*rad) / distanceAU
-	longitude := (ra - ApparentSiderealTime(jdUT)*15) * rad
-	latitude := dec * rad
-	if !finite(parallax) || parallax <= 0 || parallax >= 1 || !finite(longitude) || !finite(latitude) {
-		return nil
-	}
-	center := [3]float64{math.Cos(latitude) * math.Cos(longitude), math.Cos(latitude) * math.Sin(longitude), math.Sin(latitude)}
-	north := [3]float64{-math.Sin(latitude) * math.Cos(longitude), -math.Sin(latitude) * math.Sin(longitude), math.Cos(latitude)}
-	east := [3]float64{-math.Sin(longitude), math.Cos(longitude), 0}
-	points := make([][2]float64, samples)
-	for index := range points {
-		bearing := 2 * math.Pi * float64(index) / float64(samples)
-		radius := math.Acos(parallax)
-		var point [3]float64
-		for iteration := 0; iteration < 8; iteration++ {
-			for axis := range point {
-				point[axis] = center[axis]*math.Cos(radius) +
-					(north[axis]*math.Cos(bearing)+east[axis]*math.Sin(bearing))*math.Sin(radius)
-			}
-			lat := math.Asin(math.Max(-1, math.Min(1, point[2]))) / rad
-			// The topocentric direction is horizontal when its dot product
-			// with the geodetic zenith vanishes: cos(radius)=observer/range.
-			next := math.Acos(parallax * (pcosi(lat, 0)*math.Cos(lat*rad) + psini(lat, 0)*math.Sin(lat*rad)))
-			if math.Abs(next-radius) < 1e-14 {
-				break
-			}
-			radius = next
-		}
-		points[index] = [2]float64{math.Atan2(point[1], point[0]) / rad, math.Asin(math.Max(-1, math.Min(1, point[2]))) / rad}
-	}
-	return points
+	return MoonStateAt(jdUTC).MoonHorizon(samples)
 }