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astro/star/star.go

136 lines
3.9 KiB
Go

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package star
import (
"errors"
"math"
"time"
"b612.me/astro/basic"
)
var (
ERR_STAR_NEVER_RISE = errors.New("ERROR:极夜,星星在今日永远在地平线下!")
ERR_STAR_NEVER_DOWN = errors.New("ERROR:极昼,星星在今日永远在地平线上!")
)
// Constellation
// 计算date对应UTC世界时给定Date坐标赤经、赤纬所在的星座
func Constellation(ra, dec float64, date time.Time) string {
jde := basic.Date2JDE(date.UTC())
return basic.WhichCst(ra, dec, jde)
}
// MeanSiderealTime UTC 平恒星时
func MeanSiderealTime(date time.Time) float64 {
return basic.MeanSiderealTime(basic.Date2JDE(date.UTC()))
}
// ApparentSiderealTime UTC真恒星时
func ApparentSiderealTime(date time.Time) float64 {
return basic.ApparentSiderealTime(basic.Date2JDE(date.UTC()))
}
// RiseTime 星星升起时间
//
// date, 世界时(忽略此处时区)
// raDate瞬时赤经
// decDate瞬时赤纬
// lon经度东正西负
// lat纬度北正南负
// height高度
// aero,是否进行大气修正
func RiseTime(date time.Time, ra, dec, lon, lat, height float64, aero bool) (time.Time, error) {
var err error
if date.Hour() > 12 {
date = date.Add(time.Hour * -12)
}
jde := basic.Date2JDE(date)
_, loc := date.Zone()
timezone := float64(loc) / 3600.0
riseJde := basic.StarRiseTime(jde, ra, dec, lon, lat, height, timezone, aero)
if riseJde == -2 {
err = ERR_STAR_NEVER_RISE
}
if riseJde == -1 {
err = ERR_STAR_NEVER_DOWN
}
return basic.JDE2DateByZone(riseJde, date.Location(), true), err
}
// DownTime 星星升起时间
//
// date, 世界时(忽略此处时区)
// raDate瞬时赤经
// decDate瞬时赤纬
// lon经度东正西负
// lat纬度北正南负
// height高度
// aero,是否进行大气修正
func DownTime(date time.Time, ra, dec, lon, lat, height float64, aero bool) (time.Time, error) {
var err error
if date.Hour() > 12 {
date = date.Add(time.Hour * -12)
}
jde := basic.Date2JDE(date)
_, loc := date.Zone()
timezone := float64(loc) / 3600.0
riseJde := basic.StarDownTime(jde, ra, dec, lon, lat, height, timezone, aero)
if riseJde == -2 {
err = ERR_STAR_NEVER_RISE
}
if riseJde == -1 {
err = ERR_STAR_NEVER_DOWN
}
return basic.JDE2DateByZone(riseJde, date.Location(), true), err
}
// HourAngle 恒星时角
// 返回给定Date赤经、经度、对应date时区date时刻的太阳时角
func HourAngle(date time.Time, ra, lon float64) float64 {
jde := basic.Date2JDE(date)
_, loc := date.Zone()
timezone := float64(loc) / 3600.0
return basic.StarHourAngle(jde, ra, lon, timezone)
}
// Azimuth 恒星方位角
// 返回给定Date赤经赤纬、经纬度、对应date时区date时刻的恒星方位角正北为0向东增加
func Azimuth(date time.Time, ra, dec, lon, lat float64) float64 {
jde := basic.Date2JDE(date)
_, loc := date.Zone()
timezone := float64(loc) / 3600.0
return basic.StarAzimuth(jde, ra, dec, lon, lat, timezone)
}
// Zenith 恒星高度角
// 返回给定赤经赤纬、经纬度、对应date时区date时刻的太阳高度角
func Zenith(date time.Time, ra, dec, lon, lat float64) float64 {
jde := basic.Date2JDE(date)
_, loc := date.Zone()
timezone := float64(loc) / 3600.0
return basic.StarHeight(jde, ra, dec, lon, lat, timezone)
}
// CulminationTime 恒星中天时间
// 返回给定赤经赤纬、经纬度、对应date时区date时刻的太阳中天日期
func CulminationTime(date time.Time, ra, lon float64) time.Time {
jde := basic.Date2JDE(date)
if jde-math.Floor(jde) < 0.5 {
jde--
}
_, loc := date.Zone()
timezone := float64(loc) / 3600.0
calcJde := basic.StarCulminationTime(jde, ra, lon, timezone) - timezone/24.00
return basic.JDE2DateByZone(calcJde, date.Location(), false)
}
// InitStarDatabase 初始化恒星数据库
func InitStarDatabase() error {
return basic.LoadStarData()
}
// 通过恒星HR编号获取恒星参数
func GetStarDataByHR(hr int) (basic.StarData, error) {
return basic.StarDataByHR(hr)
}