88 lines
3.6 KiB
Go
88 lines
3.6 KiB
Go
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package astro
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import (
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"time"
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"b612.me/astro/basic"
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)
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// TimeScale 导出时间标签的时标，零值为民用 UTC / output-label time scale, defaulting to civil UTC.
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type TimeScale int
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const (
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// TimeScaleUTC 默认民用时标 / default civil time scale.
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TimeScaleUTC TimeScale = iota
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// TimeScaleUT1 UT1 读数，输出 Location 须为 nil 或 UTC / UT1 reading; output Location must be nil or UTC.
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TimeScaleUT1
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)
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// LabelIn 把民用时刻换成该时标下的时刻值 / converts a civil instant to a value in one scale.
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func LabelIn(scale TimeScale, date time.Time) time.Time {
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if scale == TimeScaleUT1 {
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return UT1FromUTC(date)
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}
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return date
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}
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// UT1FromUTC 民用时刻转 UT1 读数，以 UTC Location 承载 / converts a civil instant to a UT1 reading in a UTC Location.
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func UT1FromUTC(date time.Time) time.Time {
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return utcLabel(basic.UTC2UT1(basic.Date2JD(date.UTC())))
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}
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// UTCFromUT1 是 UT1FromUTC 的逆 / inverts UT1FromUTC.
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func UTCFromUT1(ut1 time.Time) time.Time {
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return utcLabel(basic.UT12UTC(basic.Date2JD(ut1.UTC())))
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}
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// TTFromUTC 民用时刻转 TT，按实例的 UTC 时刻取值 / converts a civil instant to TT.
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func TTFromUTC(date time.Time) time.Time {
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return utcLabel(basic.UTC2TT(basic.Date2JD(date.UTC())))
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}
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// UTCFromTT 是 TTFromUTC 的逆 / inverts TTFromUTC.
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func UTCFromTT(tt time.Time) time.Time {
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return utcLabel(basic.TT2UTC(basic.Date2JD(tt.UTC())))
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}
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// DUT1 返回民用时刻的 UT1−UTC，单位秒 / UT1−UTC in seconds.
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func DUT1(date time.Time) float64 {
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return basic.DUT1Seconds(basic.Date2JD(date.UTC()))
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}
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// TCGFromTT 地球时转地心坐标时 / converts TT to TCG.
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func TCGFromTT(tt time.Time) time.Time { return utcLabel(basic.TT2TCG(basic.Date2JD(tt.UTC()))) }
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// TTFromTCG 是 TCGFromTT 的逆 / inverts TCGFromTT.
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func TTFromTCG(tcg time.Time) time.Time { return utcLabel(basic.TCG2TT(basic.Date2JD(tcg.UTC()))) }
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// TCBFromTT 地球时转太阳系质心坐标时，采用地心近似 / converts TT to TCB using a geocentric approximation.
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func TCBFromTT(tt time.Time) time.Time { return utcLabel(basic.TT2TCB(basic.Date2JD(tt.UTC()))) }
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// TTFromTCB 是 TCBFromTT 的逆 / inverts TCBFromTT.
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func TTFromTCB(tcb time.Time) time.Time { return utcLabel(basic.TCB2TT(basic.Date2JD(tcb.UTC()))) }
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// TDBFromTT 地球时转太阳系质心力学时，采用地心近似 / converts TT to TDB using a geocentric approximation.
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func TDBFromTT(tt time.Time) time.Time { return utcLabel(basic.TT2TDB(basic.Date2JD(tt.UTC()))) }
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// TTFromTDB 是 TDBFromTT 的逆 / inverts TDBFromTT.
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func TTFromTDB(tdb time.Time) time.Time { return utcLabel(basic.TDB2TT(basic.Date2JD(tdb.UTC()))) }
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// TCBFromTDB 质心力学时转质心坐标时 / converts TDB to TCB.
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func TCBFromTDB(tdb time.Time) time.Time { return utcLabel(basic.TDB2TCB(basic.Date2JD(tdb.UTC()))) }
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// TDBFromTCB 是 TCBFromTDB 的逆 / inverts TCBFromTDB.
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func TDBFromTCB(tcb time.Time) time.Time { return utcLabel(basic.TCB2TDB(basic.Date2JD(tcb.UTC()))) }
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// TCGMinusTT 返回 TT 时刻的 TCG−TT，单位秒 / TCG−TT in seconds for a TT instant.
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func TCGMinusTT(tt time.Time) float64 { return basic.TCGMinusTTSeconds(basic.Date2JD(tt.UTC())) }
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// TCBMinusTT 返回 TT 时刻的 TCB−TT，单位秒 / TCB−TT in seconds for a TT instant.
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func TCBMinusTT(tt time.Time) float64 { return basic.TCBMinusTTSeconds(basic.Date2JD(tt.UTC())) }
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// TDBMinusTT 返回 TT 时刻的地心 TDB−TT 近似值（秒）/ geocentric TDB−TT approximation in seconds at a TT instant.
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func TDBMinusTT(tt time.Time) float64 { return basic.TDBMinusTTSeconds(basic.Date2JD(tt.UTC())) }
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func utcLabel(jd float64) time.Time {
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return basic.JD2DateByZone(jd, time.UTC, false)
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}
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