609 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			609 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| package basic
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| 
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| import (
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| 	"math"
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| 
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| 	"b612.me/astro/planet"
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| 	. "b612.me/astro/tools"
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| )
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| 
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| func MercuryL(JD float64) float64 {
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| 	return planet.WherePlanet(1, 0, JD)
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| }
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| 
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| func MercuryB(JD float64) float64 {
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| 	return planet.WherePlanet(1, 1, JD)
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| }
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| func MercuryR(JD float64) float64 {
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| 	return planet.WherePlanet(1, 2, JD)
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| }
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| func AMercuryX(JD float64) float64 {
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| 	l := MercuryL(JD)
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| 	b := MercuryB(JD)
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| 	r := MercuryR(JD)
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| 	el := planet.WherePlanet(-1, 0, JD)
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| 	eb := planet.WherePlanet(-1, 1, JD)
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| 	er := planet.WherePlanet(-1, 2, JD)
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| 	x := r*Cos(b)*Cos(l) - er*Cos(eb)*Cos(el)
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| 	return x
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| }
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| 
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| func AMercuryY(JD float64) float64 {
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| 
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| 	l := MercuryL(JD)
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| 	b := MercuryB(JD)
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| 	r := MercuryR(JD)
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| 	el := planet.WherePlanet(-1, 0, JD)
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| 	eb := planet.WherePlanet(-1, 1, JD)
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| 	er := planet.WherePlanet(-1, 2, JD)
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| 	y := r*Cos(b)*Sin(l) - er*Cos(eb)*Sin(el)
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| 	return y
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| }
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| func AMercuryZ(JD float64) float64 {
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| 	//l := MercuryL(JD)
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| 	b := MercuryB(JD)
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| 	r := MercuryR(JD)
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| 	//	el := planet.WherePlanet(-1, 0, JD)
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| 	eb := planet.WherePlanet(-1, 1, JD)
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| 	er := planet.WherePlanet(-1, 2, JD)
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| 	z := r*Sin(b) - er*Sin(eb)
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| 	return z
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| }
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| 
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| func AMercuryXYZ(JD float64) (float64, float64, float64) {
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| 	l := MercuryL(JD)
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| 	b := MercuryB(JD)
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| 	r := MercuryR(JD)
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| 	el := planet.WherePlanet(-1, 0, JD)
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| 	eb := planet.WherePlanet(-1, 1, JD)
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| 	er := planet.WherePlanet(-1, 2, JD)
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| 	x := r*Cos(b)*Cos(l) - er*Cos(eb)*Cos(el)
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| 	y := r*Cos(b)*Sin(l) - er*Cos(eb)*Sin(el)
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| 	z := r*Sin(b) - er*Sin(eb)
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| 	return x, y, z
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| }
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| 
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| func MercuryApparentRa(JD float64) float64 {
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| 	lo, bo := MercuryApparentLoBo(JD)
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| 	return LoToRa(JD, lo, bo)
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| }
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| func MercuryApparentDec(JD float64) float64 {
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| 	lo, bo := MercuryApparentLoBo(JD)
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| 	sita := Sita(JD)
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| 	dec := ArcSin(Sin(bo)*Cos(sita) + Cos(bo)*Sin(sita)*Sin(lo))
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| 	return dec
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| }
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| 
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| func MercuryApparentRaDec(JD float64) (float64, float64) {
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| 	lo, bo := MercuryApparentLoBo(JD)
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| 	return LoBoToRaDec(JD, lo, bo)
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| }
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| 
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| func EarthMercuryAway(JD float64) float64 {
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| 	x, y, z := AMercuryXYZ(JD)
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| 	to := math.Sqrt(x*x + y*y + z*z)
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| 	return to
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| }
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| 
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| func MercuryApparentLo(JD float64) float64 {
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| 	x, y, z := AMercuryXYZ(JD)
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| 	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
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| 	x, y, z = AMercuryXYZ(JD - to)
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| 	lo := math.Atan2(y, x)
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| 	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
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| 	lo = lo * 180 / math.Pi
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| 	bo = bo * 180 / math.Pi
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| 	lo = Limit360(lo)
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| 	//lo-=GXCLo(lo,bo,JD)/3600;
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| 	//bo+=GXCBo(lo,bo,JD);
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| 	lo += HJZD(JD)
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| 	return lo
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| }
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| 
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| func MercuryApparentBo(JD float64) float64 {
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| 	x, y, z := AMercuryXYZ(JD)
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| 	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
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| 	x, y, z = AMercuryXYZ(JD - to)
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| 	//lo := math.Atan2(y, x)
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| 	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
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| 	//lo = lo * 180 / math.Pi
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| 	bo = bo * 180 / math.Pi
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| 	//lo+=GXCLo(lo,bo,JD);
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| 	//bo+=GXCBo(lo,bo,JD)/3600;
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| 	//lo+=HJZD(JD);
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| 	return bo
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| }
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| 
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| func MercuryApparentLoBo(JD float64) (float64, float64) {
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| 	x, y, z := AMercuryXYZ(JD)
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| 	to := 0.0057755183 * math.Sqrt(x*x+y*y+z*z)
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| 	x, y, z = AMercuryXYZ(JD - to)
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| 	lo := math.Atan2(y, x)
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| 	bo := math.Atan2(z, math.Sqrt(x*x+y*y))
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| 	lo = lo * 180 / math.Pi
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| 	bo = bo * 180 / math.Pi
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| 	lo = Limit360(lo) + HJZD(JD)
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| 	//lo-=GXCLo(lo,bo,JD)/3600;
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| 	//bo+=GXCBo(lo,bo,JD);
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| 	return lo, bo
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| }
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| 
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| func MercuryMag(JD float64) float64 {
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| 	AwaySun := MercuryR(JD)
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| 	AwayEarth := EarthMercuryAway(JD)
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| 	Away := planet.WherePlanet(-1, 2, JD)
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| 	i := (AwaySun*AwaySun + AwayEarth*AwayEarth - Away*Away) / (2 * AwaySun * AwayEarth)
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| 	i = ArcCos(i)
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| 	Mag := -0.42 + 5*math.Log10(AwaySun*AwayEarth) + 0.0380*i - 0.000273*i*i + 0.000002*i*i*i
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| 	return FloatRound(Mag, 2)
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| }
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| 
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| func MercuryHeight(jde, lon, lat, timezone float64) float64 {
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| 	// 转换为世界时
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| 	utcJde := jde - timezone/24.0
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| 	// 计算视恒星时
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| 	ra, dec := MercuryApparentRaDec(TD2UT(utcJde, true))
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| 	st := Limit360(ApparentSiderealTime(utcJde)*15 + lon)
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| 	// 计算时角
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| 	H := Limit360(st - ra)
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| 	// 高度角、时角与天球座标三角转换公式
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| 	// sin(h)=sin(lat)*sin(dec)+cos(dec)*cos(lat)*cos(H)
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| 	sinHeight := Sin(lat)*Sin(dec) + Cos(dec)*Cos(lat)*Cos(H)
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| 	return ArcSin(sinHeight)
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| }
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| 
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| func MercuryAzimuth(jde, lon, lat, timezone float64) float64 {
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| 	// 转换为世界时
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| 	utcJde := jde - timezone/24.0
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| 	// 计算视恒星时
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| 	ra, dec := MercuryApparentRaDec(TD2UT(utcJde, true))
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| 	st := Limit360(ApparentSiderealTime(utcJde)*15 + lon)
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| 	// 计算时角
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| 	H := Limit360(st - ra)
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| 	// 三角转换公式
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| 	tanAzimuth := Sin(H) / (Cos(H)*Sin(lat) - Tan(dec)*Cos(lat))
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| 	Azimuth := ArcTan(tanAzimuth)
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| 	if Azimuth < 0 {
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| 		if H/15 < 12 {
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| 			return Azimuth + 360
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| 		}
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| 		return Azimuth + 180
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| 	}
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| 	if H/15 < 12 {
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| 		return Azimuth + 180
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| 	}
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| 	return Azimuth
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| }
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| 
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| func MercuryHourAngle(JD, Lon, TZ float64) float64 {
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| 	startime := Limit360(ApparentSiderealTime(JD-TZ/24)*15 + Lon)
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| 	timeangle := startime - MercuryApparentRa(TD2UT(JD-TZ/24.0, true))
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| 	if timeangle < 0 {
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| 		timeangle += 360
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| 	}
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| 	return timeangle
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| }
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| 
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| func MercuryCulminationTime(jde, lon, timezone float64) float64 {
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| 	//jde 世界时,非力学时,当地时区 0时,无需转换力学时
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| 	//ra,dec 瞬时天球座标,非J2000等时间天球坐标
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| 	jde = math.Floor(jde) + 0.5
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| 	JD1 := jde + Limit360(360-MercuryHourAngle(jde, lon, timezone))/15.0/24.0*0.99726851851851851851
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| 	limitHA := func(jde, lon, timezone float64) float64 {
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| 		ha := MercuryHourAngle(jde, lon, timezone)
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| 		if ha < 180 {
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| 			ha += 360
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| 		}
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| 		return ha
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| 	}
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| 	for {
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| 		JD0 := JD1
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| 		stDegree := limitHA(JD0, lon, timezone) - 360
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| 		stDegreep := (limitHA(JD0+0.000005, lon, timezone) - limitHA(JD0-0.000005, lon, timezone)) / 0.00001
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| 		JD1 = JD0 - stDegree/stDegreep
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| 		if math.Abs(JD1-JD0) <= 0.00001 {
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| 			break
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| 		}
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| 	}
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| 	return JD1
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| }
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| 
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| func MercuryRiseTime(JD, Lon, Lat, TZ, ZS, HEI float64) float64 {
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| 	return mercuryRiseDown(JD, Lon, Lat, TZ, ZS, HEI, true)
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| }
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| 
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| func MercuryDownTime(JD, Lon, Lat, TZ, ZS, HEI float64) float64 {
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| 	return mercuryRiseDown(JD, Lon, Lat, TZ, ZS, HEI, false)
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| }
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| 
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| func mercuryRiseDown(JD, Lon, Lat, TZ, ZS, HEI float64, isRise bool) float64 {
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| 	var An float64
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| 	JD = math.Floor(JD) + 0.5
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| 	ntz := math.Round(Lon / 15)
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| 	if ZS != 0 {
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| 		An = -0.8333
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| 	}
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| 	An = An - HeightDegreeByLat(HEI, Lat)
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| 	tztime := MercuryCulminationTime(JD, Lon, ntz)
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| 	if MercuryHeight(tztime, Lon, Lat, ntz) < An {
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| 		return -2 //极夜
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| 	}
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| 	if MercuryHeight(tztime-0.5, Lon, Lat, ntz) > An {
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| 		return -1 //极昼
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| 	}
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| 	dec := HSunApparentDec(TD2UT(tztime-ntz/24, true))
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| 	//(sin(ho)-sin(φ)*sin(δ2))/(cos(φ)*cos(δ2))
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| 	tmp := (Sin(An) - Sin(dec)*Sin(Lat)) / (Cos(dec) * Cos(Lat))
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| 	var rise float64
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| 	if math.Abs(tmp) <= 1 {
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| 		rzsc := ArcCos(tmp) / 15
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| 		if isRise {
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| 			rise = tztime - rzsc/24 - 25.0/24.0/60.0
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| 		} else {
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| 			rise = tztime + rzsc/24 - 25.0/24.0/60.0
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| 		}
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| 	} else {
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| 		rise = tztime
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| 		i := 0
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| 		//TODO:使用二分法计算
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| 		for MercuryHeight(rise, Lon, Lat, ntz) > An {
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| 			i++
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| 			if isRise {
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| 				rise -= 15.0 / 60.0 / 24.0
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| 			} else {
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| 				rise += 15.0 / 60.0 / 24.0
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| 			}
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| 			if i > 48 {
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| 				break
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| 			}
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| 		}
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| 	}
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| 	JD1 := rise
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| 	for {
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| 		JD0 := JD1
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| 		stDegree := MercuryHeight(JD0, Lon, Lat, ntz) - An
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| 		stDegreep := (MercuryHeight(JD0+0.000005, Lon, Lat, ntz) - MercuryHeight(JD0-0.000005, Lon, Lat, ntz)) / 0.00001
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| 		JD1 = JD0 - stDegree/stDegreep
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| 		if math.Abs(JD1-JD0) <= 0.00001 {
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| 			break
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| 		}
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| 	}
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| 	return JD1 - ntz/24 + TZ/24
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| }
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| 
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| // Pos
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| 
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| const MERCURY_S_PERIOD = 1 / ((1 / 87.9691) - (1 / 365.256363004))
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| 
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| func mercuryConjunction(jde float64, next uint8) float64 {
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| 	//0=last 1=next
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| 	decSub := func(jde float64) float64 {
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| 		sub := Limit360(MercuryApparentLo(jde) - HSunApparentLo(jde))
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| 		if sub > 180 {
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| 			sub -= 360
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| 		}
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| 		if sub < -180 {
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| 			sub += 360
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| 		}
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| 		return sub
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| 	}
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| 	nowSub := decSub(jde)
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| 	// pos 大于0:远离太阳 小于0:靠近太阳
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| 	pos := math.Abs(decSub(jde+1/86400.0)) - math.Abs(nowSub)
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| 	if pos >= 0 && next == 1 && nowSub > 0 {
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| 		jde += MERCURY_S_PERIOD/8.0 + 2
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| 	}
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| 	if pos >= 0 && next == 1 && nowSub < 0 {
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| 		jde += MERCURY_S_PERIOD/6.0 + 2
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| 	}
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| 	if pos <= 0 && next == 0 && nowSub < 0 {
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| 		jde -= MERCURY_S_PERIOD/8.0 + 2
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| 	}
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| 	if pos <= 0 && next == 0 && nowSub > 0 {
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| 		jde -= MERCURY_S_PERIOD/6.0 + 2
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| 	}
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| 	for {
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| 		nowSub := decSub(jde)
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| 		pos := math.Abs(decSub(jde+1/86400.0)) - math.Abs(nowSub)
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| 		if math.Abs(nowSub) > 12 || (pos > 0 && next == 1) || (pos < 0 && next == 0) {
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| 			if next == 1 {
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| 				jde += 2
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| 			} else {
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| 				jde -= 2
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| 			}
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| 			continue
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| 		}
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| 		break
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| 	}
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| 	JD1 := jde
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| 	for {
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| 		JD0 := JD1
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| 		stDegree := decSub(JD0)
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| 		stDegreep := (decSub(JD0+0.000005) - decSub(JD0-0.000005)) / 0.00001
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| 		JD1 = JD0 - stDegree/stDegreep
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| 		if math.Abs(JD1-JD0) <= 0.00001 {
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| 			break
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| 		}
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| 	}
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| 	return TD2UT(JD1, false)
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| }
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| 
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| func LastMercuryConjunction(jde float64) float64 {
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| 	return mercuryConjunction(jde, 0)
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| }
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| 
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| func NextMercuryConjunction(jde float64) float64 {
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| 	return mercuryConjunction(jde, 1)
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| }
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| 
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| func NextMercuryInferiorConjunction(jde float64) float64 {
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| 	date := NextMercuryConjunction(jde)
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| 	if EarthMercuryAway(date) > EarthAway(date) {
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| 		return NextMercuryConjunction(date + 2)
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| 	}
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| 	return date
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| }
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| 
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| func NextMercurySuperiorConjunction(jde float64) float64 {
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| 	date := NextMercuryConjunction(jde)
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| 	if EarthMercuryAway(date) < EarthAway(date) {
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| 		return NextMercuryConjunction(date + 2)
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| 	}
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| 	return date
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| }
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| 
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| func LastMercuryInferiorConjunction(jde float64) float64 {
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| 	date := LastMercuryConjunction(jde)
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| 	if EarthMercuryAway(date) > EarthAway(date) {
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| 		return LastMercuryConjunction(date - 2)
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| 	}
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| 	return date
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| }
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| 
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| func LastMercurySuperiorConjunction(jde float64) float64 {
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| 	date := LastMercuryConjunction(jde)
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| 	if EarthMercuryAway(date) < EarthAway(date) {
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| 		return LastMercuryConjunction(date - 2)
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| 	}
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| 	return date
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| }
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| 
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| func mercuryRetrograde(jde float64) float64 {
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| 	//0=last 1=next
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| 	decSunSub := func(jde float64) float64 {
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| 		sub := Limit360(MercuryApparentRa(jde) - SunApparentRa(jde))
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| 		if sub > 180 {
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| 			sub -= 360
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| 		}
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| 		if sub < -180 {
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| 			sub += 360
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| 		}
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| 		return sub
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| 	}
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| 	decSub := func(jde float64, val float64) float64 {
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| 		sub := MercuryApparentRa(jde+val) - MercuryApparentRa(jde-val)
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| 		if sub > 180 {
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| 			sub -= 360
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| 		}
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| 		if sub < -180 {
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| 			sub += 360
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| 		}
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| 		return sub / (2 * val)
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| 	}
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| 	lastHe := LastMercuryConjunction(jde)
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| 	nextHe := NextMercuryConjunction(jde)
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| 	nowSub := decSunSub(jde)
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| 	if nowSub > 0 {
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| 		jde = lastHe + ((nextHe - lastHe) / 5.0 * 3.5)
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| 	} else {
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| 		jde = lastHe + ((nextHe - lastHe) / 5.5)
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| 	}
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| 	for {
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| 		nowSub := decSub(jde, 1.0/86400.0)
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| 		if math.Abs(nowSub) > 0.55 {
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| 			jde += 2
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| 			continue
 | ||
| 		}
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| 		break
 | ||
| 	}
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| 	JD1 := jde
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| 	for {
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| 		JD0 := JD1
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| 		stDegree := decSub(JD0, 2.0/86400.0)
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| 		stDegreep := (decSub(JD0+15.0/86400.0, 2.0/86400.0) - decSub(JD0-15.0/86400.0, 2.0/86400.0)) / (30.0 / 86400.0)
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| 		JD1 = JD0 - stDegree/stDegreep
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| 		if math.Abs(JD1-JD0) <= 30.0/86400.0 {
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| 			break
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| 		}
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| 	}
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| 	JD1 = JD1 - 15.0/86400.0
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| 	min := JD1
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| 	minRa := 100.0
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| 	for i := 0.0; i < 60.0; i++ {
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| 		tmp := decSub(JD1+i*0.5/86400.0, 0.5/86400.0)
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| 		if math.Abs(tmp) < math.Abs(minRa) {
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| 			minRa = tmp
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| 			min = JD1 + i*0.5/86400.0
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| 		}
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| 	}
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| 	//fmt.Println((min - lastHe) / (nextHe - lastHe))
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| 	return TD2UT(min, false)
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| }
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| 
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| func NextMercuryRetrograde(jde float64) float64 {
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| 	date := mercuryRetrograde(jde)
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| 	if date < jde {
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| 		nextHe := NextMercuryConjunction(jde)
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| 		return mercuryRetrograde(nextHe + 2)
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| 	}
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| 	return date
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| }
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| 
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| func LastMercuryRetrograde(jde float64) float64 {
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| 	lastHe := LastMercuryConjunction(jde)
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| 	date := mercuryRetrograde(lastHe + 2)
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| 	if date > jde {
 | ||
| 		lastLastHe := LastMercuryConjunction(lastHe - 2)
 | ||
| 		return mercuryRetrograde(lastLastHe + 2)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func NextMercuryProgradeToRetrograde(jde float64) float64 {
 | ||
| 	date := NextMercuryRetrograde(jde)
 | ||
| 	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
 | ||
| 	if sub > 180 {
 | ||
| 		return NextMercuryRetrograde(date + MERCURY_S_PERIOD/2)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func NextMercuryRetrogradeToPrograde(jde float64) float64 {
 | ||
| 	date := NextMercuryRetrograde(jde)
 | ||
| 	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
 | ||
| 	if sub < 180 {
 | ||
| 		return NextMercuryRetrograde(date + 12)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func LastMercuryProgradeToRetrograde(jde float64) float64 {
 | ||
| 	date := LastMercuryRetrograde(jde)
 | ||
| 	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
 | ||
| 	if sub > 180 {
 | ||
| 		return LastMercuryRetrograde(date - 12)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func LastMercuryRetrogradeToPrograde(jde float64) float64 {
 | ||
| 	date := LastMercuryRetrograde(jde)
 | ||
| 	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
 | ||
| 	if sub < 180 {
 | ||
| 		return LastMercuryRetrograde(date - MERCURY_S_PERIOD/2)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func MercurySunElongation(jde float64) float64 {
 | ||
| 	lo1, bo1 := MercuryApparentLoBo(jde)
 | ||
| 	lo2 := SunApparentLo(jde)
 | ||
| 	bo2 := HSunTrueBo(jde)
 | ||
| 	return StarAngularSeparation(lo1, bo1, lo2, bo2)
 | ||
| }
 | ||
| func mercuryGreatestElongation(jde float64) float64 {
 | ||
| 	decSunSub := func(jde float64) float64 {
 | ||
| 		sub := Limit360(MercuryApparentRa(jde) - SunApparentRa(jde))
 | ||
| 		if sub > 180 {
 | ||
| 			sub -= 360
 | ||
| 		}
 | ||
| 		if sub < -180 {
 | ||
| 			sub += 360
 | ||
| 		}
 | ||
| 		return sub
 | ||
| 	}
 | ||
| 	decSub := func(jde float64, val float64) float64 {
 | ||
| 		sub := MercurySunElongation(jde+val) - MercurySunElongation(jde-val)
 | ||
| 		if sub > 180 {
 | ||
| 			sub -= 360
 | ||
| 		}
 | ||
| 		if sub < -180 {
 | ||
| 			sub += 360
 | ||
| 		}
 | ||
| 		return sub / (2 * val)
 | ||
| 	}
 | ||
| 	lastHe := LastMercuryConjunction(jde)
 | ||
| 	nextHe := NextMercuryConjunction(jde)
 | ||
| 	nowSub := decSunSub(jde)
 | ||
| 	if nowSub > 0 {
 | ||
| 		jde = lastHe + ((nextHe - lastHe) / 5.0 * 2.0)
 | ||
| 	} else {
 | ||
| 		jde = lastHe + ((nextHe - lastHe) / 6.0)
 | ||
| 	}
 | ||
| 	for {
 | ||
| 		nowSub := decSub(jde, 1.0/86400.0)
 | ||
| 		if math.Abs(nowSub) > 0.4 {
 | ||
| 			jde += 2
 | ||
| 			continue
 | ||
| 		}
 | ||
| 		break
 | ||
| 	}
 | ||
| 	JD1 := jde
 | ||
| 	for {
 | ||
| 		JD0 := JD1
 | ||
| 		stDegree := decSub(JD0, 2.0/86400.0)
 | ||
| 		stDegreep := (decSub(JD0+15.0/86400.0, 2.0/86400.0) - decSub(JD0-15.0/86400.0, 2.0/86400.0)) / (30.0 / 86400.0)
 | ||
| 		JD1 = JD0 - stDegree/stDegreep
 | ||
| 		if math.Abs(JD1-JD0) <= 30.0/86400.0 {
 | ||
| 			break
 | ||
| 		}
 | ||
| 	}
 | ||
| 	JD1 = JD1 - 15.0/86400.0
 | ||
| 	min := JD1
 | ||
| 	minRa := 100.0
 | ||
| 	for i := 0.0; i < 60.0; i++ {
 | ||
| 		tmp := decSub(JD1+i*0.5/86400.0, 0.5/86400.0)
 | ||
| 		if math.Abs(tmp) < math.Abs(minRa) {
 | ||
| 			minRa = tmp
 | ||
| 			min = JD1 + i*0.5/86400.0
 | ||
| 		}
 | ||
| 	}
 | ||
| 	//fmt.Println((min - lastHe) / (nextHe - lastHe))
 | ||
| 	return TD2UT(min, false)
 | ||
| }
 | ||
| 
 | ||
| func NextMercuryGreatestElongation(jde float64) float64 {
 | ||
| 	date := mercuryGreatestElongation(jde)
 | ||
| 	if date < jde {
 | ||
| 		nextHe := NextMercuryConjunction(jde)
 | ||
| 		return mercuryGreatestElongation(nextHe + 2)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func LastMercuryGreatestElongation(jde float64) float64 {
 | ||
| 	lastHe := LastMercuryConjunction(jde)
 | ||
| 	date := mercuryGreatestElongation(lastHe + 2)
 | ||
| 	if date > jde {
 | ||
| 		lastLastHe := LastMercuryConjunction(lastHe - 2)
 | ||
| 		return mercuryGreatestElongation(lastLastHe + 2)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func NextMercuryGreatestElongationEast(jde float64) float64 {
 | ||
| 	date := NextMercuryGreatestElongation(jde)
 | ||
| 	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
 | ||
| 	if sub > 180 {
 | ||
| 		return NextMercuryGreatestElongation(date + 1)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func NextMercuryGreatestElongationWest(jde float64) float64 {
 | ||
| 	date := NextMercuryGreatestElongation(jde)
 | ||
| 	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
 | ||
| 	if sub < 180 {
 | ||
| 		return NextMercuryGreatestElongation(date + 1)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func LastMercuryGreatestElongationEast(jde float64) float64 {
 | ||
| 	date := LastMercuryGreatestElongation(jde)
 | ||
| 	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
 | ||
| 	if sub > 180 {
 | ||
| 		return LastMercuryGreatestElongation(date - 1)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 | ||
| 
 | ||
| func LastMercuryGreatestElongationWest(jde float64) float64 {
 | ||
| 	date := LastMercuryGreatestElongation(jde)
 | ||
| 	sub := Limit360(MercuryApparentRa(date) - SunApparentRa(date))
 | ||
| 	if sub < 180 {
 | ||
| 		return LastMercuryGreatestElongation(date - 1)
 | ||
| 	}
 | ||
| 	return date
 | ||
| }
 |