starainrt
3ffdbe0034
- 新增日食、月食、本地可见性、中心线、半影区域、SVG 图示与沙罗周期信息 - 新增行星冲合、留、方照、物理星历、视直径、相位、亮肢角、轨道节点等计算 - 新增木星伽利略卫星位置、现象与接触事件计算 - 新增恒星星表、星座判定、自行修正与观测辅助能力 - 新增 coord、formula、orbit、sundial、lite/sun、lite/moon 等扩展包 - 完善农历年号、月相英文别名、视差角、大气质量、折射、日晷与双星计算 - 增加 NASA、JPL Horizons、IMCCE 等回归测试数据与基线测试 - 重构基础算法文件组织，补充大量公开 API 注释和语义回归测试 - 更新中文和英文 README，补充示例、精度说明、SVG 配图
104 lines
3.0 KiB
Go
104 lines
3.0 KiB
Go
package basic
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import (
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"errors"
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"math"
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. "b612.me/astro/tools"
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)
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var (
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ErrNeverRise = errors.New("rise event does not occur on this date")
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ErrNeverSet = errors.New("set event does not occur on this date")
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ErrNotOnThisDate = errors.New("rise/set event occurs on adjacent date")
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)
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func StandardAltitudeStar(aero bool, observerHeight, lat float64) float64 {
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targetAltitude := 0.0
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if aero {
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targetAltitude = -0.566667
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}
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return targetAltitude - HeightDegreeByLat(observerHeight, lat)
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}
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func StandardAltitudeSun(zenithShift, observerHeight, lat float64) float64 {
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targetAltitude := 0.0
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if zenithShift != 0 {
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targetAltitude = -0.8333
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}
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return targetAltitude - HeightDegreeByLat(observerHeight, lat)
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}
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func StandardAltitudePlanet(aeroCorrection, observerHeight, lat float64) float64 {
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targetAltitude := 0.0
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if aeroCorrection != 0 {
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targetAltitude = -0.566667
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}
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return targetAltitude - HeightDegreeByLat(observerHeight, lat)
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}
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func StandardAltitudeMoon(zenithShift, observerHeight, lat float64) float64 {
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targetAltitude := 0.0
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if zenithShift != 0 {
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targetAltitude = -0.83333
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}
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return targetAltitude - HeightDegreeByLat(observerHeight, lat)
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}
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type planetCulminationFunc func(float64, float64, float64) float64
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type planetHeightFunc func(float64, float64, float64, float64) float64
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type planetDeclinationFunc func(float64) float64
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func planetRiseDown(jd, lon, lat, timezone, aeroCorrection, observerHeight float64, isRise bool, culmination planetCulminationFunc, height planetHeightFunc, declination planetDeclinationFunc) (float64, error) {
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jd = math.Floor(jd) + 0.5
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localTimezone := math.Round(lon / 15)
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targetAltitude := StandardAltitudePlanet(aeroCorrection, observerHeight, lat)
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culminationJD := culmination(jd, lon, localTimezone)
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if height(culminationJD, lon, lat, localTimezone) < targetAltitude {
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return 0, ErrNeverRise
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}
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if height(culminationJD-0.5, lon, lat, localTimezone) > targetAltitude {
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return 0, ErrNeverSet
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}
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dec := declination(TD2UT(culminationJD-localTimezone/24, true))
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cosHourAngle := (Sin(targetAltitude) - Sin(dec)*Sin(lat)) / (Cos(dec) * Cos(lat))
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var eventJD float64
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if math.Abs(cosHourAngle) <= 1 {
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hourOffset := ArcCos(cosHourAngle) / 15
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if isRise {
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eventJD = culminationJD - hourOffset/24 - 25.0/24.0/60.0
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} else {
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eventJD = culminationJD + hourOffset/24 - 25.0/24.0/60.0
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}
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} else {
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eventJD = culminationJD
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steps := 0
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for height(eventJD, lon, lat, localTimezone) > targetAltitude {
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steps++
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if isRise {
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eventJD -= 15.0 / 60.0 / 24.0
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} else {
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eventJD += 15.0 / 60.0 / 24.0
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}
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if steps > 48 {
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break
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}
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}
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}
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estimateJD := eventJD
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for {
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prevJD := estimateJD
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altitudeDelta := height(prevJD, lon, lat, localTimezone) - targetAltitude
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altitudeSlope := (height(prevJD+0.000005, lon, lat, localTimezone) - height(prevJD-0.000005, lon, lat, localTimezone)) / 0.00001
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estimateJD = prevJD - altitudeDelta/altitudeSlope
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if math.Abs(estimateJD-prevJD) <= 0.00001 {
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break
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}
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}
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return estimateJD - localTimezone/24 + timezone/24, nil
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}
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