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

moon/max_declination.go

@@ -0,0 +1,78 @@
+package moon
+
+import (
+	"time"
+
+	"b612.me/astro/basic"
+)
+
+// MaximumDeclinationInfo 月球最大赤纬事件 / maximum lunar declination event.
+type MaximumDeclinationInfo struct {
+	// Time 事件时刻，UTC / event time in UTC.
+	Time time.Time
+	// Declination 该时刻的地心赤纬，单位度 / geocentric declination at the event, in degrees.
+	Declination float64
+}
+
+// MaximumNorthDeclinationsInMonth 指定年月内的所有月球最大北赤纬事件 / all maximum northern lunar declination events in the given Gregorian month.
+func MaximumNorthDeclinationsInMonth(year int, month time.Month) []MaximumDeclinationInfo {
+	return convertMaximumDeclinationInfos(basic.MoonMaximumNorthDeclinations(year, month))
+}
+
+// MaximumSouthDeclinationsInMonth 指定年月内的所有月球最大南赤纬事件 / all maximum southern lunar declination events in the given Gregorian month.
+func MaximumSouthDeclinationsInMonth(year int, month time.Month) []MaximumDeclinationInfo {
+	return convertMaximumDeclinationInfos(basic.MoonMaximumSouthDeclinations(year, month))
+}
+
+// LastMaximumNorthDeclination 指定时刻之前最近一次月球最大北赤纬 / last maximum northern lunar declination at or before date.
+func LastMaximumNorthDeclination(date time.Time) MaximumDeclinationInfo {
+	return convertMaximumDeclinationInfo(date, basic.LastMoonMaximumNorthDeclination(timeToUTJDE(date)))
+}
+
+// NextMaximumNorthDeclination 指定时刻之后最近一次月球最大北赤纬 / next maximum northern lunar declination after date.
+func NextMaximumNorthDeclination(date time.Time) MaximumDeclinationInfo {
+	return convertMaximumDeclinationInfo(date, basic.NextMoonMaximumNorthDeclination(timeToUTJDE(date)))
+}
+
+// ClosestMaximumNorthDeclination 离指定时刻最近一次月球最大北赤纬 / closest maximum northern lunar declination to date.
+func ClosestMaximumNorthDeclination(date time.Time) MaximumDeclinationInfo {
+	return convertMaximumDeclinationInfo(date, basic.ClosestMoonMaximumNorthDeclination(timeToUTJDE(date)))
+}
+
+// LastMaximumSouthDeclination 指定时刻之前最近一次月球最大南赤纬 / last maximum southern lunar declination at or before date.
+func LastMaximumSouthDeclination(date time.Time) MaximumDeclinationInfo {
+	return convertMaximumDeclinationInfo(date, basic.LastMoonMaximumSouthDeclination(timeToUTJDE(date)))
+}
+
+// NextMaximumSouthDeclination 指定时刻之后最近一次月球最大南赤纬 / next maximum southern lunar declination after date.
+func NextMaximumSouthDeclination(date time.Time) MaximumDeclinationInfo {
+	return convertMaximumDeclinationInfo(date, basic.NextMoonMaximumSouthDeclination(timeToUTJDE(date)))
+}
+
+// ClosestMaximumSouthDeclination 离指定时刻最近一次月球最大南赤纬 / closest maximum southern lunar declination to date.
+func ClosestMaximumSouthDeclination(date time.Time) MaximumDeclinationInfo {
+	return convertMaximumDeclinationInfo(date, basic.ClosestMoonMaximumSouthDeclination(timeToUTJDE(date)))
+}
+
+func convertMaximumDeclinationInfos(events []basic.DeclinationEvent) []MaximumDeclinationInfo {
+	result := make([]MaximumDeclinationInfo, 0, len(events))
+	for _, event := range events {
+		result = append(result, convertMaximumDeclinationInfo(time.Time{}, event))
+	}
+	return result
+}
+
+func convertMaximumDeclinationInfo(date time.Time, event basic.DeclinationEvent) MaximumDeclinationInfo {
+	location := time.UTC
+	if date.Location() != nil {
+		location = date.Location()
+	}
+	return MaximumDeclinationInfo{
+		Time:        basic.JDE2DateByZone(event.JDE, location, false),
+		Declination: event.Declination,
+	}
+}
+
+func timeToUTJDE(date time.Time) float64 {
+	return basic.Date2JDE(date.UTC())
+}