b612
044f2f4381
- 新增半解析、旧模型、自定义与多源堆叠星历实例，提供 Context、Instance、SPK 读取及状态与视位置计算 - 统一太阳、月球和行星实例接口，扩展黄经穿越、留、相位、最近角距、偕日可见、任意高度升落、轨道节点及凌日等天象查询 - 完善日月食、月掩与凌日的月缘剖面、有限盘面接触、站心修正、局地可见性、全球路径和地图输出 - 新增 SVG、GeoJSON、KML 天象输出及凌日、月掩和月缘地形相关缓存与几何求解 - 新增恒星星表导入与查询，支持 CSV、Hipparcos、BSC5、Stellarium 等格式及名称、交叉标识、锥面检索和星等过滤 - 补充 IAU 2006、地球定向、折射消光、大气观测、轨道传播及半解析行星/月球数据支持 - 将默认未来民用时标切换为 TimeScaleLeapHour，更新 2027–2400 农历速查表、中文日期解析和时区边界处理 - 增加事件基线、跨模型回归、几何边界、月缘地形和输出契约测试，完善中英文手册、示例资源、NOTICE 与忽略规则
81 lines
4.4 KiB
Go
81 lines
4.4 KiB
Go
package basic
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import (
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"math"
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"b612.me/astro/internal/geodata"
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)
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// LunarEclipseShadowGeometry 是食甚时刻的地影几何。
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// 注意单位口径：Gamma 用地球赤道半径，而两个影半径用度——后者是 NASA 月食图上 P./U. Radius 的口径，
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// 换成地球赤道半径要乘以月球处的地球视差（弧度）。
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// LunarEclipseShadowGeometry is the terrestrial-shadow geometry at maximum eclipse. Gamma is in Earth
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// equatorial radii while the two shadow radii are in degrees, matching the P./U. Radius convention of
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// NASA lunar-eclipse charts; multiply a radius by the Earth's parallax at the Moon to get Earth radii.
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type LunarEclipseShadowGeometry struct {
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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。
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// Gamma is the least distance from the Moon's centre to the shadow axis, in Earth equatorial radii.
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Gamma float64
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// PenumbralRadiusDegrees 与 UmbralRadiusDegrees 是半影、本影在地影轴垂直面上的角半径，单位度。
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// PenumbralRadiusDegrees and UmbralRadiusDegrees are the penumbral and umbral angular radii on the
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// plane perpendicular to the shadow axis, in degrees.
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PenumbralRadiusDegrees float64
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UmbralRadiusDegrees float64
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// MoonDistanceEarthRadii 是食甚时的地心月距，单位地球赤道半径。
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// MoonDistanceEarthRadii is the geocentric lunar distance at greatest eclipse, in Earth equatorial radii.
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MoonDistanceEarthRadii float64
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// AxisDegrees 是食甚时月心到地影轴的角距，即 NASA 月食图上那列 Axis。
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// 它与 Gamma 是同一个量的两种刻度：Gamma 除以月球处的地球视差就是它。
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// AxisDegrees is the angular distance from the Moon's centre to the shadow axis at greatest eclipse,
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// the column NASA lunar-eclipse charts print as Axis. It is the same quantity as Gamma on a different
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// scale: divide Gamma by the Earth's parallax at the Moon.
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AxisDegrees float64
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}
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// LunarEclipseShadowGeometryAt 用 Danjon 影半径模型计算食甚时刻的地影几何。
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// LunarEclipseShadowGeometryAt computes the shadow geometry at maximum eclipse with the Danjon shadow model.
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func LunarEclipseShadowGeometryAt(maximumJDE float64) LunarEclipseShadowGeometry {
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return lunarEclipseShadowGeometryAt(maximumJDE, lunarEclipseShadowDanjon)
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}
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// LunarEclipseShadowGeometryChauvenetAt 用 Chauvenet 影半径模型计算食甚时刻的地影几何。
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// LunarEclipseShadowGeometryChauvenetAt computes the shadow geometry with the Chauvenet shadow model.
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func LunarEclipseShadowGeometryChauvenetAt(maximumJDE float64) LunarEclipseShadowGeometry {
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return lunarEclipseShadowGeometryAt(maximumJDE, lunarEclipseShadowChauvenet)
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}
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// LunarEclipseShadowGeometryAtModel 按结果里记录的影半径模型取地影几何。
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// LunarEclipseShadowGeometryAtModel picks the shadow geometry by the model recorded in a result.
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func LunarEclipseShadowGeometryAtModel(maximumJDE float64, model LunarEclipseShadowModel) LunarEclipseShadowGeometry {
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if model == LunarEclipseShadowModelChauvenet {
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return LunarEclipseShadowGeometryChauvenetAt(maximumJDE)
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}
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return LunarEclipseShadowGeometryAt(maximumJDE)
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}
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func lunarEclipseShadowGeometryAt(maximumJDE float64, shadowModel lunarEclipseShadowModel) LunarEclipseShadowGeometry {
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return lunarEclipseShadowGeometryAtWithInstance(maximumJDE, shadowModel, nil)
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}
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func lunarEclipseShadowGeometryAtWithInstance(maximumJDE float64, shadowModel lunarEclipseShadowModel, inst *Instance) LunarEclipseShadowGeometry {
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evaluate := func(jde float64) lunarShadowState {
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return computeLunarShadowStateWithInstance(jde, shadowModel, inst)
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}
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state := evaluate(maximumJDE)
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moonDistanceKM := HMoonAwayWithInstance(maximumJDE, inst)
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// 影半径是以地心为顶点的角量，除以月球处的地球视差就换成地球赤道半径。
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earthParallax := geodata.EarthEquatorialRadiusKM / moonDistanceKM
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_, _, _, _, minimumDistance := refineLunarEclipseMaximumWithEvaluator(maximumJDE, evaluate)
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if earthParallax <= 0 {
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return LunarEclipseShadowGeometry{}
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}
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return LunarEclipseShadowGeometry{
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Gamma: minimumDistance / earthParallax,
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PenumbralRadiusDegrees: state.penumbraRadiusRad * 180 / math.Pi,
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UmbralRadiusDegrees: state.umbraRadiusRad * 180 / math.Pi,
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MoonDistanceEarthRadii: moonDistanceKM / geodata.EarthEquatorialRadiusKM,
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// 平面 x 向东（黄经差）、y 向北（黄纬和），方位角自北向东量。
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AxisDegrees: minimumDistance * 180 / math.Pi,
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}
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}
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