54 lines
1.3 KiB
Go
54 lines
1.3 KiB
Go
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package planet
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import . "b612.me/astro/tools"
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// SunLo 太阳几何黄经
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func SunLo(jd float64) float64 {
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T := (jd - 2451545) / 365250
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SunLo := 280.4664567 + 360007.6982779*T + 0.03032028*T*T + T*T*T/49931 - T*T*T*T/15299 - T*T*T*T*T/1988000
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return Limit360(SunLo)
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}
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func SunM(JD float64) float64 {
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T := (JD - 2451545) / 36525
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sunM := 357.5291092 + 35999.0502909*T - 0.0001559*T*T - 0.00000048*T*T*T
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return Limit360(sunM)
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}
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// Earthe 地球偏心率
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func Earthe(JD float64) float64 {
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T := (JD - 2451545) / 36525
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Earthe := 0.016708617 - 0.000042037*T - 0.0000001236*T*T
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return Earthe
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}
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func EarthPI(JD float64) float64 {
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T := (JD - 2451545) / 36525
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return 102.93735 + 1.71953*T + 000046*T*T
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}
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func SunMidFun(JD float64) float64 {
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T := (JD - 2451545) / 36525
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M := SunM(JD)
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SunMidFun := (1.9146-0.004817*T-0.000014*T*T)*Sin(M) + (0.019993-0.000101*T)*Sin(2*M) + 0.00029*Sin(3*M)
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return SunMidFun
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}
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func SunTrueLo(JD float64) float64 {
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SunTrueLo := SunLo(JD) + SunMidFun(JD)
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return SunTrueLo
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}
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func SunApparentLo(JD float64) float64 {
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T := (JD - 2451545) / 36525
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SunApparentLo := SunTrueLo(JD) - 0.00569 - 0.00478*Sin(125.04-1934.136*T)
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return SunApparentLo
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}
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func Distance(jd float64) float64 {
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f := SunMidFun(jd)
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m := SunM(jd)
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e := Earthe(jd)
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return 1.000001018 * (1 - e*e) / (1 + e*Cos(f+m))
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}
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