b612
16c62a97d5
- 新增时标、ΔT 模型、质心时间与 UT1 支持 - 改进日月食、月掩、行星事件及路径边界计算 - 完善恒星三维自行与动态距离传播 - 扩展 SVG、GeoJSON、KML 输出与底层距离换算工具 - 整理中英文手册、示例资源及回归测试
100 lines
4.8 KiB
Go
100 lines
4.8 KiB
Go
package eclipse
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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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// LunarEclipseGeocentricPanel 汇总月食图上各面板所需的食甚时刻地心量。
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// LunarEclipseGeocentricPanel carries the geocentric quantities that lunar-eclipse panels print.
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type LunarEclipseGeocentricPanel struct {
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// FullMoon 望，即地心视黄经相差 180° 的时刻；它与该次月食的食甚不是同一时刻。
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// FullMoon is the instant of full moon, when the geocentric apparent ecliptic longitudes differ by
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// 180 degrees; it is not the same instant as greatest eclipse.
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FullMoon time.Time
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FullMoonJDE float64
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// DeltaTSeconds 是食甚时刻实际使用的 ΔT。
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// DeltaTSeconds is the ΔT used at greatest eclipse.
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DeltaTSeconds float64
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SunRightAscensionDeg float64
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SunDeclinationDeg float64
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SunSemidiameterArcsec float64
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SunParallaxArcsec float64
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MoonRightAscensionDeg float64
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MoonDeclinationDeg float64
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MoonSemidiameterArcsec float64
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MoonParallaxArcsec float64
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// ShadowModel 是影半径模型，决定影半径与食分。
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// ShadowModel is the shadow-radius model that fixes the radii and magnitudes.
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ShadowModel LunarEclipseShadowModel
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// PenumbralRadiusDegrees 与 UmbralRadiusDegrees 是食甚时的半影、本影半径，单位度。
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// PenumbralRadiusDegrees and UmbralRadiusDegrees are the shadow radii at greatest eclipse, in degrees.
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PenumbralRadiusDegrees float64
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UmbralRadiusDegrees float64
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// Gamma 是月心到地影轴的最小距离，单位地球赤道半径；AxisDegrees 是同一个量的角度制数值。
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// Gamma is the minimum Moon-centre-to-axis distance in Earth equatorial radii; AxisDegrees is the same in degrees.
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Gamma float64
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AxisDegrees float64
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// MoonDistanceEarthRadii 是食甚时的地心月距。
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// MoonDistanceEarthRadii is the geocentric Moon distance at greatest eclipse.
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MoonDistanceEarthRadii float64
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// PenumbralMagnitude 与 UmbralMagnitude 与 LunarEclipseInfo 同口径。
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// PenumbralMagnitude and UmbralMagnitude follow the same convention as LunarEclipseInfo.
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PenumbralMagnitude float64
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UmbralMagnitude float64
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// Ephemeris 是所用影半径模型名称。
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// Ephemeris names the shadow-radius model used.
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Ephemeris string
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}
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// LunarEclipseGeocentricPanelAt 计算给定日期月食的地心量面板，使用 Danjon 影半径模型。
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// LunarEclipseGeocentricPanelAt computes the geocentric panel of one lunar eclipse with the Danjon shadow model.
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func LunarEclipseGeocentricPanelAt(date time.Time) (LunarEclipseGeocentricPanel, bool) {
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return lunarEclipseGeocentricPanelAt(date, basic.LunarEclipseDanjon)
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}
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// LunarEclipseGeocentricPanelChauvenet 计算给定日期月食的地心量面板，使用 Chauvenet 影半径模型。
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// LunarEclipseGeocentricPanelChauvenet computes the geocentric panel with the Chauvenet shadow model.
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func LunarEclipseGeocentricPanelChauvenet(date time.Time) (LunarEclipseGeocentricPanel, bool) {
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return lunarEclipseGeocentricPanelAt(date, basic.LunarEclipseChauvenet)
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}
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func lunarEclipseGeocentricPanelAt(date time.Time, calculator func(float64) basic.LunarEclipseResult) (LunarEclipseGeocentricPanel, bool) {
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seed := timeToTTJDE(date)
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fullMoonJDE := basic.CalcMoonSHByJDE(seed, 1)
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result := calculator(fullMoonJDE)
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if result.Type == basic.LunarEclipseNone {
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return LunarEclipseGeocentricPanel{}, false
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}
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geometry := basic.LunarEclipseShadowGeometryAtModel(result.Maximum, result.ShadowModel)
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ephemeris := "Danjon"
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if result.ShadowModel == basic.LunarEclipseShadowModelChauvenet {
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ephemeris = "Chauvenet"
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}
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panel := LunarEclipseGeocentricPanel{
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FullMoon: ttJDEToTime(fullMoonJDE, date.Location()),
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FullMoonJDE: fullMoonJDE,
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DeltaTSeconds: basic.DeltaT(result.Maximum, true),
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ShadowModel: LunarEclipseShadowModel(result.ShadowModel),
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PenumbralRadiusDegrees: geometry.PenumbralRadiusDegrees,
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UmbralRadiusDegrees: geometry.UmbralRadiusDegrees,
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Gamma: geometry.Gamma,
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AxisDegrees: geometry.AxisDegrees,
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MoonDistanceEarthRadii: geometry.MoonDistanceEarthRadii,
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PenumbralMagnitude: result.PenumbralMagnitude,
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UmbralMagnitude: result.Magnitude,
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Ephemeris: ephemeris,
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}
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panel.SunRightAscensionDeg, panel.SunDeclinationDeg = basic.SunApparentRaDec(result.Maximum)
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panel.MoonRightAscensionDeg, panel.MoonDeclinationDeg = basic.HMoonTrueRaDec(result.Maximum)
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panel.SunSemidiameterArcsec = basic.SolarEclipseSunSemidiameter(result.Maximum, basic.SolarEclipseSunRadiusStandard)
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panel.MoonSemidiameterArcsec = basic.MoonSemidiameter(result.Maximum)
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panel.SunParallaxArcsec = horizontalParallaxArcsec(panel.SunSemidiameterArcsec, horizontalParallaxSunRatio)
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panel.MoonParallaxArcsec = horizontalParallaxArcsec(panel.MoonSemidiameterArcsec, horizontalParallaxMoonRatio)
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return panel, true
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}
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