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
583 lines
25 KiB
Go
583 lines
25 KiB
Go
package eclipse
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import (
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"math"
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"time"
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"b612.me/astro/basic"
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)
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const (
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localSolarEclipseSynodicMonthDays = 29.530588853
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localSolarEclipseSearchLimit = 6000
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localSolarEclipseSearchEpsilonDay = 1e-8
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localSolarEclipseLatitudeLimitDeg = 2.0
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)
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type localSolarEclipseCalculator struct {
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global func(float64) basic.SolarEclipseResult
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local func(float64, float64, float64, float64) basic.LocalSolarEclipseResult
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}
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type localSolarEclipseQueryMode int
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const (
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localSolarEclipseQueryVisible localSolarEclipseQueryMode = iota
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localSolarEclipseQueryGeometric
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)
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// LocalSolarEclipseContactPoint 表示站心日食在日面上的接触点方位。
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// LocalSolarEclipseContactPoint describes a local solar eclipse contact point on the Sun limb.
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type LocalSolarEclipseContactPoint struct {
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// Label 是接触标签，如 C1/C2/C3/C4。
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// Label is the contact label, such as C1/C2/C3/C4.
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Label string
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// Time 是该接触时刻，保持用户输入时区。
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// Time is the contact time, preserving the input timezone.
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Time time.Time
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// ContactPositionAngle 是日面接触点位置角，从天球北点起向东量，单位度。
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// ContactPositionAngle is the Sun-limb contact position angle from celestial north toward east, in degrees.
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ContactPositionAngle float64
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// ContactClockwiseAngle 是图面上从北点顺时针量到接触点的角度，单位度。
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// ContactClockwiseAngle is the chart clockwise angle from north to the contact point, in degrees.
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ContactClockwiseAngle float64
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// MoonCenterPositionAngle 是月心相对日心的位置角，从北点起向东量，单位度。
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// MoonCenterPositionAngle is the Moon-center position angle from the Sun center, in degrees.
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MoonCenterPositionAngle float64
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}
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// LocalSolarEclipseInfo 站心日食信息, local solar eclipse information.
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//
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// 所有时刻字段都保持用户输入的时区。
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// 不存在的阶段使用零值 time.Time。
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type LocalSolarEclipseInfo struct {
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// Model 日食月亮半径模型, eclipse lunar radius model.
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Model SolarEclipseRadiusModel
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// Type 站心食型, local eclipse type.
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Type SolarEclipseType
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// HasSaros 存在沙罗序列信息, has Saros series metadata.
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HasSaros bool
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// Saros 是沙罗序列信息，包括系列号、系列内序号和总成员数。
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// Saros is Saros series metadata with the series number, member index, and total member count.
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Saros SarosInfo
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// Longitude 观测点经度，东正西负, observer longitude, east positive.
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Longitude float64
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// Latitude 观测点纬度，北正南负, observer latitude, north positive.
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Latitude float64
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// Height 观测点海拔高度，单位米, observer height in meters.
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Height float64
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// GreatestEclipse 食甚时刻, greatest eclipse.
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GreatestEclipse time.Time
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// PartialStart 偏食始 / 初亏, partial eclipse begins.
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PartialStart time.Time
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// PartialEnd 偏食终 / 复圆, partial eclipse ends.
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PartialEnd time.Time
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// CentralStart 中心食始；对全食为食既，对环食为环食始, central eclipse begins.
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CentralStart time.Time
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// CentralEnd 中心食终；对全食为生光，对环食为环食终, central eclipse ends.
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CentralEnd time.Time
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// Magnitude 站心食分, local eclipse magnitude.
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Magnitude float64
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// Obscuration 食甚时太阳视圆面遮蔽率, obscuration at greatest eclipse.
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Obscuration float64
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// Separation 食甚时日月中心角距，单位度, center separation at greatest eclipse in degrees.
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Separation float64
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// SunAltitude 食甚时太阳高度角，单位度, Sun altitude at greatest eclipse in degrees.
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SunAltitude float64
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// SunAzimuth 食甚时太阳方位角，单位度, Sun azimuth at greatest eclipse in degrees.
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SunAzimuth float64
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// VisibleAtGreatest 食甚时太阳中心在地平线上方, Sun center above horizon at greatest eclipse.
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VisibleAtGreatest bool
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// ContactPoints 是各接触时刻在日面上的接触点方位。
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// ContactPoints are Sun-limb contact position angles at eclipse contacts.
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ContactPoints []LocalSolarEclipseContactPoint
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// HasPartial 存在偏食阶段, has partial phase.
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HasPartial bool
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// HasCentral 存在中心食阶段, has central phase.
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HasCentral bool
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// HasAnnular 存在环食阶段, has annular phase.
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HasAnnular bool
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// HasTotal 存在全食阶段, has total phase.
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HasTotal bool
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}
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// LocalSolarEclipseOnDate 当地站心日食查询 / local topocentric solar eclipse query.
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// Determine whether a visible local solar eclipse overlaps the local date, using NASA bulletin Split-K by default.
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func LocalSolarEclipseOnDate(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
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return LocalSolarEclipseOnDateNASABulletinSplitK(date, lon, lat, height)
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}
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// LocalSolarEclipseOnDateNASABulletinSplitK 当地站心日食查询（NASA bulletin Split-K） / local topocentric solar eclipse query with NASA bulletin Split-K.
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// Determine whether a visible local solar eclipse overlaps the local date with the NASA bulletin Split-K model.
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func LocalSolarEclipseOnDateNASABulletinSplitK(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
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return localSolarEclipseOnDate(date, lon, lat, height, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
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}
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// LocalSolarEclipseOnDateIAUSingleK 当地站心日食查询（IAU Single-K） / local topocentric solar eclipse query with IAU Single-K.
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// Determine whether a visible local solar eclipse overlaps the local date with the IAU Single-K model.
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func LocalSolarEclipseOnDateIAUSingleK(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
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return localSolarEclipseOnDate(date, lon, lat, height, localSolarEclipseIAUSingleK, localSolarEclipseQueryVisible)
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}
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// GeometricLocalSolarEclipseOnDate 当地站心几何日食查询 / local geometric solar eclipse query.
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// Determine whether a geometric local solar eclipse overlaps the local date, using NASA bulletin Split-K by default.
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func GeometricLocalSolarEclipseOnDate(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
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return GeometricLocalSolarEclipseOnDateNASABulletinSplitK(date, lon, lat, height)
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}
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// GeometricLocalSolarEclipseOnDateNASABulletinSplitK 当地站心几何日食查询（NASA bulletin Split-K） / local geometric solar eclipse query with NASA bulletin Split-K.
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// Determine whether a geometric local solar eclipse overlaps the local date with the NASA bulletin Split-K model.
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func GeometricLocalSolarEclipseOnDateNASABulletinSplitK(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
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return localSolarEclipseOnDate(date, lon, lat, height, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryGeometric)
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}
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// GeometricLocalSolarEclipseOnDateIAUSingleK 当地站心几何日食查询（IAU Single-K） / local geometric solar eclipse query with IAU Single-K.
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// Determine whether a geometric local solar eclipse overlaps the local date with the IAU Single-K model.
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func GeometricLocalSolarEclipseOnDateIAUSingleK(date time.Time, lon, lat, height float64) (LocalSolarEclipseInfo, bool) {
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return localSolarEclipseOnDate(date, lon, lat, height, localSolarEclipseIAUSingleK, localSolarEclipseQueryGeometric)
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}
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func localSolarEclipseOnDate(
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date time.Time,
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lon, lat, height float64,
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calculator localSolarEclipseCalculator,
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mode localSolarEclipseQueryMode,
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) (LocalSolarEclipseInfo, bool) {
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location := date.Location()
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dayStart, dayMid, dayEnd := solarEclipseLocalDayBounds(date)
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candidateTT := basic.CalcMoonSHByJDE(solarEclipseTimeToTTJDE(dayMid), 0)
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if !isPotentialLocalSolarEclipse(candidateTT) {
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return LocalSolarEclipseInfo{}, false
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}
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globalResult := calculator.global(candidateTT)
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if globalResult.Type == basic.SolarEclipseNone {
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return LocalSolarEclipseInfo{}, false
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}
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result := calculator.local(globalResult.GreatestEclipse, lon, lat, height)
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if result.Type == basic.SolarEclipseNone {
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return LocalSolarEclipseInfo{}, false
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}
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info := localSolarEclipseInfoFromBasic(result, lon, lat, height, location)
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if !localSolarEclipseOverlapsDate(info, dayStart, dayEnd) {
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return LocalSolarEclipseInfo{}, false
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}
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if mode == localSolarEclipseQueryVisible && !localSolarEclipseVisibleOnDate(info, dayStart, dayEnd) {
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return LocalSolarEclipseInfo{}, false
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}
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return info, true
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}
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// LastLocalSolarEclipse 上次站心日食 / previous local solar eclipse.
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// Previous visible local solar eclipse, using NASA bulletin Split-K by default.
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func LastLocalSolarEclipse(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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return LastLocalSolarEclipseNASABulletinSplitK(date, lon, lat, height)
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}
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// LastLocalSolarEclipseNASABulletinSplitK 上次站心日食（NASA bulletin Split-K） / previous local solar eclipse with NASA bulletin Split-K.
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// Previous visible local solar eclipse with the NASA bulletin Split-K model.
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func LastLocalSolarEclipseNASABulletinSplitK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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info, _ := searchLocalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
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return info
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}
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// LastLocalSolarEclipseIAUSingleK 上次站心日食（IAU Single-K） / previous local solar eclipse with IAU Single-K.
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// Previous visible local solar eclipse with the IAU Single-K model.
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func LastLocalSolarEclipseIAUSingleK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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info, _ := searchLocalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseIAUSingleK, localSolarEclipseQueryVisible)
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return info
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}
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// LastGeometricLocalSolarEclipse 上次站心几何日食 / previous geometric local solar eclipse.
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// Previous geometric local solar eclipse, using NASA bulletin Split-K by default.
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func LastGeometricLocalSolarEclipse(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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return LastGeometricLocalSolarEclipseNASABulletinSplitK(date, lon, lat, height)
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}
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// LastGeometricLocalSolarEclipseNASABulletinSplitK 上次站心几何日食（NASA bulletin Split-K） / previous geometric local solar eclipse with NASA bulletin Split-K.
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// Previous geometric local solar eclipse with the NASA bulletin Split-K model.
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func LastGeometricLocalSolarEclipseNASABulletinSplitK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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info, _ := searchLocalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryGeometric)
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return info
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}
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// LastGeometricLocalSolarEclipseIAUSingleK 上次站心几何日食（IAU Single-K） / previous geometric local solar eclipse with IAU Single-K.
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// Previous geometric local solar eclipse with the IAU Single-K model.
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func LastGeometricLocalSolarEclipseIAUSingleK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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info, _ := searchLocalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseIAUSingleK, localSolarEclipseQueryGeometric)
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return info
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}
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// NextLocalSolarEclipse 下次站心日食 / next local solar eclipse.
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// Next visible local solar eclipse, using NASA bulletin Split-K by default.
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func NextLocalSolarEclipse(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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return NextLocalSolarEclipseNASABulletinSplitK(date, lon, lat, height)
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}
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// NextLocalSolarEclipseNASABulletinSplitK 下次站心日食（NASA bulletin Split-K） / next local solar eclipse with NASA bulletin Split-K.
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// Next visible local solar eclipse with the NASA bulletin Split-K model.
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func NextLocalSolarEclipseNASABulletinSplitK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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info, _ := searchLocalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
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return info
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}
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// NextLocalSolarEclipseIAUSingleK 下次站心日食（IAU Single-K） / next local solar eclipse with IAU Single-K.
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// Next visible local solar eclipse with the IAU Single-K model.
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func NextLocalSolarEclipseIAUSingleK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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info, _ := searchLocalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseIAUSingleK, localSolarEclipseQueryVisible)
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return info
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}
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// NextGeometricLocalSolarEclipse 下次站心几何日食 / next geometric local solar eclipse.
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// Next geometric local solar eclipse, using NASA bulletin Split-K by default.
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func NextGeometricLocalSolarEclipse(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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return NextGeometricLocalSolarEclipseNASABulletinSplitK(date, lon, lat, height)
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}
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// NextGeometricLocalSolarEclipseNASABulletinSplitK 下次站心几何日食（NASA bulletin Split-K） / next geometric local solar eclipse with NASA bulletin Split-K.
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// Next geometric local solar eclipse with the NASA bulletin Split-K model.
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func NextGeometricLocalSolarEclipseNASABulletinSplitK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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info, _ := searchLocalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryGeometric)
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return info
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}
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// NextGeometricLocalSolarEclipseIAUSingleK 下次站心几何日食（IAU Single-K） / next geometric local solar eclipse with IAU Single-K.
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// Next geometric local solar eclipse with the IAU Single-K model.
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func NextGeometricLocalSolarEclipseIAUSingleK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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info, _ := searchLocalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseIAUSingleK, localSolarEclipseQueryGeometric)
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return info
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}
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// ClosestLocalSolarEclipse 最近一次站心日食 / closest local solar eclipse.
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// Closest visible local solar eclipse, using NASA bulletin Split-K by default.
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func ClosestLocalSolarEclipse(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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return ClosestLocalSolarEclipseNASABulletinSplitK(date, lon, lat, height)
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}
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// ClosestLocalSolarEclipseNASABulletinSplitK 最近一次站心日食（NASA bulletin Split-K） / closest local solar eclipse with NASA bulletin Split-K.
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// Closest visible local solar eclipse with the NASA bulletin Split-K model.
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func ClosestLocalSolarEclipseNASABulletinSplitK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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last, hasLast := searchLocalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
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next, hasNext := searchLocalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryVisible)
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return closestLocalSolarEclipse(date, last, hasLast, next, hasNext)
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}
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// ClosestLocalSolarEclipseIAUSingleK 最近一次站心日食（IAU Single-K） / closest local solar eclipse with IAU Single-K.
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// Closest visible local solar eclipse with the IAU Single-K model.
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func ClosestLocalSolarEclipseIAUSingleK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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last, hasLast := searchLocalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseIAUSingleK, localSolarEclipseQueryVisible)
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next, hasNext := searchLocalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseIAUSingleK, localSolarEclipseQueryVisible)
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return closestLocalSolarEclipse(date, last, hasLast, next, hasNext)
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}
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// ClosestGeometricLocalSolarEclipse 最近一次站心几何日食 / closest geometric local solar eclipse.
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// Closest geometric local solar eclipse, using NASA bulletin Split-K by default.
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func ClosestGeometricLocalSolarEclipse(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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return ClosestGeometricLocalSolarEclipseNASABulletinSplitK(date, lon, lat, height)
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}
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// ClosestGeometricLocalSolarEclipseNASABulletinSplitK 最近一次站心几何日食（NASA bulletin Split-K） / closest geometric local solar eclipse with NASA bulletin Split-K.
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// Closest geometric local solar eclipse with the NASA bulletin Split-K model.
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func ClosestGeometricLocalSolarEclipseNASABulletinSplitK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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last, hasLast := searchLocalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryGeometric)
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next, hasNext := searchLocalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseNASABulletinSplitK, localSolarEclipseQueryGeometric)
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return closestLocalSolarEclipse(date, last, hasLast, next, hasNext)
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}
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// ClosestGeometricLocalSolarEclipseIAUSingleK 最近一次站心几何日食（IAU Single-K） / closest geometric local solar eclipse with IAU Single-K.
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// Closest geometric local solar eclipse with the IAU Single-K model.
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func ClosestGeometricLocalSolarEclipseIAUSingleK(date time.Time, lon, lat, height float64) LocalSolarEclipseInfo {
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last, hasLast := searchLocalSolarEclipse(date, lon, lat, height, -1, true, localSolarEclipseIAUSingleK, localSolarEclipseQueryGeometric)
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next, hasNext := searchLocalSolarEclipse(date, lon, lat, height, 1, false, localSolarEclipseIAUSingleK, localSolarEclipseQueryGeometric)
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return closestLocalSolarEclipse(date, last, hasLast, next, hasNext)
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}
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func closestLocalSolarEclipse(
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date time.Time,
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last LocalSolarEclipseInfo,
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hasLast bool,
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next LocalSolarEclipseInfo,
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hasNext bool,
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) LocalSolarEclipseInfo {
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switch {
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case hasLast && !hasNext:
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return last
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case !hasLast && hasNext:
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return next
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case !hasLast && !hasNext:
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return LocalSolarEclipseInfo{}
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}
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lastDistance := math.Abs(date.Sub(last.GreatestEclipse).Seconds())
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nextDistance := math.Abs(next.GreatestEclipse.Sub(date).Seconds())
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if lastDistance <= nextDistance {
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return last
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}
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return next
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}
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func searchLocalSolarEclipse(
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date time.Time,
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lon, lat, height float64,
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direction int,
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includeCurrent bool,
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calculator localSolarEclipseCalculator,
|
||
mode localSolarEclipseQueryMode,
|
||
) (LocalSolarEclipseInfo, bool) {
|
||
targetTT := solarEclipseTimeToTTJDE(date)
|
||
candidateTT := basic.CalcMoonSHByJDE(targetTT, 0)
|
||
|
||
for i := 0; i < localSolarEclipseSearchLimit; i++ {
|
||
if isPotentialLocalSolarEclipse(candidateTT) {
|
||
globalResult := calculator.global(candidateTT)
|
||
if globalResult.Type != basic.SolarEclipseNone {
|
||
result := calculator.local(globalResult.GreatestEclipse, lon, lat, height)
|
||
if result.Type != basic.SolarEclipseNone {
|
||
info := localSolarEclipseInfoFromBasic(result, lon, lat, height, date.Location())
|
||
if (mode != localSolarEclipseQueryVisible || localSolarEclipseVisible(info)) &&
|
||
localSolarEclipseMatchesDirection(result.GreatestEclipse, targetTT, direction, includeCurrent) {
|
||
return info, true
|
||
}
|
||
}
|
||
}
|
||
}
|
||
candidateTT = basic.CalcMoonSHByJDE(candidateTT+float64(direction)*localSolarEclipseSynodicMonthDays, 0)
|
||
}
|
||
|
||
return LocalSolarEclipseInfo{}, false
|
||
}
|
||
|
||
func isPotentialLocalSolarEclipse(newMoonTT float64) bool {
|
||
return math.Abs(basic.HMoonTrueBo(newMoonTT)) <= localSolarEclipseLatitudeLimitDeg
|
||
}
|
||
|
||
func localSolarEclipseMatchesDirection(greatestTT, targetTT float64, direction int, includeCurrent bool) bool {
|
||
delta := greatestTT - targetTT
|
||
if math.Abs(delta) <= localSolarEclipseSearchEpsilonDay {
|
||
return direction < 0 && includeCurrent
|
||
}
|
||
if direction > 0 {
|
||
return delta > 0
|
||
}
|
||
return delta < 0
|
||
}
|
||
|
||
func localSolarEclipseInfoFromBasic(
|
||
result basic.LocalSolarEclipseResult,
|
||
lon, lat, height float64,
|
||
location *time.Location,
|
||
) LocalSolarEclipseInfo {
|
||
info := localSolarEclipseInfoFieldsFromBasic(result, lon, lat, height, location)
|
||
info.ContactPoints = localSolarEclipseContactPointsFromBasic(result, lon, lat, height, location)
|
||
return info
|
||
}
|
||
|
||
func localSolarEclipseInfoFromDiagram(
|
||
diagram basic.LocalSolarEclipseDiagramResult,
|
||
lon, lat, height float64,
|
||
location *time.Location,
|
||
) LocalSolarEclipseInfo {
|
||
info := localSolarEclipseInfoFieldsFromBasic(diagram.Eclipse, lon, lat, height, location)
|
||
info.ContactPoints = localSolarEclipseContactPointsFromFrames(diagram.Frames, location)
|
||
return info
|
||
}
|
||
|
||
func localSolarEclipseInfoFieldsFromBasic(
|
||
result basic.LocalSolarEclipseResult,
|
||
lon, lat, height float64,
|
||
location *time.Location,
|
||
) LocalSolarEclipseInfo {
|
||
visibleThreshold := localSolarEclipseVisibilityThreshold(height, lat)
|
||
saros, hasSaros := solarSarosInfo(result.GreatestEclipse)
|
||
return LocalSolarEclipseInfo{
|
||
Model: mapBasicSolarEclipseModel(result.Model),
|
||
Type: mapBasicSolarEclipseType(result.Type),
|
||
HasSaros: hasSaros,
|
||
Saros: saros,
|
||
Longitude: lon,
|
||
Latitude: lat,
|
||
Height: height,
|
||
GreatestEclipse: solarEclipseTTJDEToTime(result.GreatestEclipse, location),
|
||
PartialStart: solarEclipseTTJDEToTime(result.PartialStart, location),
|
||
PartialEnd: solarEclipseTTJDEToTime(result.PartialEnd, location),
|
||
CentralStart: solarEclipseTTJDEToTime(result.CentralStart, location),
|
||
CentralEnd: solarEclipseTTJDEToTime(result.CentralEnd, location),
|
||
Magnitude: result.Magnitude,
|
||
Obscuration: result.Obscuration,
|
||
Separation: result.Separation,
|
||
SunAltitude: result.SunAltitude,
|
||
SunAzimuth: result.SunAzimuth,
|
||
VisibleAtGreatest: result.SunAltitude > visibleThreshold,
|
||
HasPartial: result.HasPartial,
|
||
HasCentral: result.HasCentral,
|
||
HasAnnular: result.HasAnnular,
|
||
HasTotal: result.HasTotal,
|
||
}
|
||
}
|
||
|
||
func localSolarEclipseContactPointsFromBasic(
|
||
result basic.LocalSolarEclipseResult,
|
||
lon, lat, height float64,
|
||
location *time.Location,
|
||
) []LocalSolarEclipseContactPoint {
|
||
if !result.HasPartial {
|
||
return nil
|
||
}
|
||
options := basic.LocalSolarEclipseDiagramOptions{StepDays: 1}
|
||
var diagram basic.LocalSolarEclipseDiagramResult
|
||
if result.Model == basic.SolarEclipseModelIAUSingleK {
|
||
diagram = basic.LocalSolarEclipseDiagramIAUSingleK(result.GreatestEclipse, lon, lat, height, options)
|
||
} else {
|
||
diagram = basic.LocalSolarEclipseDiagramNASABulletinSplitK(result.GreatestEclipse, lon, lat, height, options)
|
||
}
|
||
return localSolarEclipseContactPointsFromFrames(diagram.Frames, location)
|
||
}
|
||
|
||
func localSolarEclipseContactPointsFromFrames(
|
||
frames []basic.LocalSolarEclipseDiagramFrame,
|
||
location *time.Location,
|
||
) []LocalSolarEclipseContactPoint {
|
||
contacts := make([]LocalSolarEclipseContactPoint, 0, 4)
|
||
for _, frame := range frames {
|
||
for _, label := range localSolarEclipseFrameLabels(frame) {
|
||
switch label {
|
||
case "C1", "C2", "C3", "C4":
|
||
contactPA := frame.PositionAngle
|
||
if (label == "C2" || label == "C3") && frame.MoonRadius >= frame.SunRadius {
|
||
contactPA = normalizeSolarEclipseDegree360(contactPA + 180)
|
||
}
|
||
contacts = append(contacts, LocalSolarEclipseContactPoint{
|
||
Label: label,
|
||
Time: solarEclipseTTJDEToTime(frame.JDE, location),
|
||
ContactPositionAngle: contactPA,
|
||
ContactClockwiseAngle: normalizeSolarEclipseDegree360(360 - contactPA),
|
||
MoonCenterPositionAngle: frame.PositionAngle,
|
||
})
|
||
}
|
||
}
|
||
}
|
||
return contacts
|
||
}
|
||
|
||
func localSolarEclipseFrameLabels(frame basic.LocalSolarEclipseDiagramFrame) []string {
|
||
if len(frame.Labels) > 0 {
|
||
return frame.Labels
|
||
}
|
||
if frame.Label == "" {
|
||
return nil
|
||
}
|
||
return []string{frame.Label}
|
||
}
|
||
|
||
func localSolarEclipseOverlapsDate(info LocalSolarEclipseInfo, dayStart, dayEnd time.Time) bool {
|
||
eventStart, eventEnd, ok := localSolarEclipseRange(info)
|
||
if !ok {
|
||
return false
|
||
}
|
||
return !eventEnd.Before(dayStart) && eventStart.Before(dayEnd)
|
||
}
|
||
|
||
func localSolarEclipseRange(info LocalSolarEclipseInfo) (time.Time, time.Time, bool) {
|
||
if !info.HasPartial {
|
||
return time.Time{}, time.Time{}, false
|
||
}
|
||
return info.PartialStart, info.PartialEnd, true
|
||
}
|
||
|
||
func localSolarEclipseVisible(info LocalSolarEclipseInfo) bool {
|
||
eventStart, eventEnd, ok := localSolarEclipseRange(info)
|
||
if !ok {
|
||
return false
|
||
}
|
||
return localSolarEclipseVisibleDuring(info, eventStart, eventEnd)
|
||
}
|
||
|
||
func localSolarEclipseVisibleOnDate(info LocalSolarEclipseInfo, dayStart, dayEnd time.Time) bool {
|
||
eventStart, eventEnd, ok := localSolarEclipseRange(info)
|
||
if !ok {
|
||
return false
|
||
}
|
||
segmentStart := maxLocalSolarTime(eventStart, dayStart)
|
||
segmentEnd := minLocalSolarTime(eventEnd, dayEnd)
|
||
if !segmentStart.Before(segmentEnd) {
|
||
return false
|
||
}
|
||
return localSolarEclipseVisibleDuring(info, segmentStart, segmentEnd)
|
||
}
|
||
|
||
func localSolarEclipseVisibleDuring(info LocalSolarEclipseInfo, start, end time.Time) bool {
|
||
if !start.Before(end) && !start.Equal(end) {
|
||
return false
|
||
}
|
||
|
||
if localSolarEclipseAltitudeVisible(start, info) || localSolarEclipseAltitudeVisible(end, info) {
|
||
return true
|
||
}
|
||
|
||
for dayStart, _, _ := solarEclipseLocalDayBounds(start); !dayStart.After(end); dayStart = nextSolarEclipseLocalDayStart(dayStart) {
|
||
_, culminationSeed, _ := solarEclipseLocalDayBounds(dayStart)
|
||
culmination := solarCulminationTime(culminationSeed, info.Longitude)
|
||
if culmination.Before(start) || culmination.After(end) {
|
||
continue
|
||
}
|
||
if localSolarEclipseAltitudeVisible(culmination, info) {
|
||
return true
|
||
}
|
||
}
|
||
|
||
return false
|
||
}
|
||
|
||
func localSolarEclipseAltitudeVisible(date time.Time, info LocalSolarEclipseInfo) bool {
|
||
return solarAltitude(date, info.Longitude, info.Latitude) > localSolarEclipseVisibilityThreshold(info.Height, info.Latitude)
|
||
}
|
||
|
||
func localSolarEclipseVisibilityThreshold(height, latitude float64) float64 {
|
||
if height <= 0 {
|
||
return 0
|
||
}
|
||
return -basic.HeightDegreeByLat(height, latitude)
|
||
}
|
||
|
||
func normalizeSolarEclipseDegree360(angle float64) float64 {
|
||
angle = math.Mod(angle, 360)
|
||
if angle < 0 {
|
||
angle += 360
|
||
}
|
||
return angle
|
||
}
|
||
|
||
func maxLocalSolarTime(a, b time.Time) time.Time {
|
||
if a.After(b) {
|
||
return a
|
||
}
|
||
return b
|
||
}
|
||
|
||
func minLocalSolarTime(a, b time.Time) time.Time {
|
||
if a.Before(b) {
|
||
return a
|
||
}
|
||
return b
|
||
}
|
||
|
||
var (
|
||
localSolarEclipseNASABulletinSplitK = localSolarEclipseCalculator{
|
||
global: basic.SolarEclipseNASABulletinSplitK,
|
||
local: basic.LocalSolarEclipseNASABulletinSplitK,
|
||
}
|
||
localSolarEclipseIAUSingleK = localSolarEclipseCalculator{
|
||
global: basic.SolarEclipseIAUSingleK,
|
||
local: basic.LocalSolarEclipseIAUSingleK,
|
||
}
|
||
)
|