- fix: Correct sun.TrueBo calculation, now using basic.HSunTrueBo for correct solar latitude

- fix: Rename GetSunDownTime to GetSunSetTime in basic/sun.go and update related calls/outputs
- fix: Update test cases to use new method and error constant names

- improve: Rename all DownTime/Down functions to SetTime/Set for consistency
- improve: Standardize ERR_XXX_NEVER_DOWN error constants to ERR_XXX_NEVER_SET, with ERR_XXX_NEVER_DOWN kept as compatibility alias
- improve: More standard naming for interfaces and errors to improve maintainability and readability

venus/venus.go

@@ -11,7 +11,7 @@ import (
 var (
 	ERR_VENUS_NEVER_RISE = errors.New("ERROR:极夜，金星今日永远在地平线下！")
 	ERR_VENUS_NEVER_SET  = errors.New("ERROR:极昼，金星今日永远在地平线上！")
-	// ERR_VENUS_NEVER_DOWN deprecated -- use ERR_VENUS_NEVER_SET instead
+	// ERR_VENUS_NEVER_DOWN deprecated: -- use ERR_VENUS_NEVER_SET instead
 	ERR_VENUS_NEVER_DOWN = ERR_VENUS_NEVER_SET
 )
 
@@ -129,6 +129,7 @@ func RiseTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, e
 	return basic.JDE2DateByZone(riseJde, date.Location(), true), err
 }
 
+// deprecated: -- use SetTime instead
 // DownTime 落下时间
 // date，取日期，时区忽略
 // lon，经度，东正西负
@@ -136,6 +137,16 @@ func RiseTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, e
 // height，高度
 // aero，true时进行大气修正
 func DownTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, error) {
+	return SetTime(date, lon, lat, height, aero)
+}
+
+// SetTime 落下时间
+// date，取日期，时区忽略
+// lon，经度，东正西负
+// lat，纬度，北正南负
+// height，高度
+// aero，true时进行大气修正
+func SetTime(date time.Time, lon, lat, height float64, aero bool) (time.Time, error) {
 	var err error
 	var aeroFloat float64
 	if aero {