b612
2bf8478639
- 新增日月食中心带、偏食带、阴影足迹、等时线、食分线及升落边界计算，支持极区与混合食拓扑 - 新增日食单时刻阴影求解器、站心状态查询、批量采样和 ΔT 覆盖接口 - 重构恒星与行星月掩路径，补充有限盘面接触、站心修正、掩带宽度、极区投影及升落边界 - 扩展 SVG 与 GeoJSON 输出，支持详细面板、全球/极区/地球投影、边界闭合、时间标记和拓扑签名 - 扩展日月食候选搜索、局地搜索、沙罗序列预计算与范围外推，补充系列锚点和成员一致性校验 - 补齐古历纪年、儒略历独有闰日、多公历候选、历法改革跨日及精确日期运算接口 - 优化 ΔT、章动、恒星时、月球地平线、事件根搜索和本地星历缓存，降低重复计算开销并提升边界稳定
386 lines
15 KiB
Go
386 lines
15 KiB
Go
package eclipse
|
||
|
||
import (
|
||
"math"
|
||
"time"
|
||
|
||
"b612.me/astro/basic"
|
||
)
|
||
|
||
const (
|
||
solarEclipseSynodicMonthDays = 29.530588853
|
||
solarEclipseSearchLimit = 36
|
||
solarEclipseSearchEpsilonDay = 1e-8
|
||
solarEclipseLatitudeLimitDeg = 2.0
|
||
)
|
||
|
||
type solarEclipseCalculator func(float64) basic.SolarEclipseResult
|
||
|
||
// SolarEclipseRadiusModel 日食月亮半径模型, lunar radius model for solar eclipses.
|
||
type SolarEclipseRadiusModel string
|
||
|
||
const (
|
||
// SolarEclipseModelIAUSingleK IAU 单一 k 值模型, IAU single-k model.
|
||
SolarEclipseModelIAUSingleK SolarEclipseRadiusModel = "iau_single_k"
|
||
// SolarEclipseModelNASABulletinSplitK NASA bulletin 分裂 k 值模型, NASA bulletin split-k model.
|
||
SolarEclipseModelNASABulletinSplitK SolarEclipseRadiusModel = "nasa_bulletin_split_k"
|
||
)
|
||
|
||
// SolarEclipseType 全局日食食型, global solar eclipse type.
|
||
type SolarEclipseType string
|
||
|
||
const (
|
||
// SolarEclipseNone 无日食, no solar eclipse.
|
||
SolarEclipseNone SolarEclipseType = "none"
|
||
// SolarEclipsePartial 日偏食, partial solar eclipse.
|
||
SolarEclipsePartial SolarEclipseType = "partial"
|
||
// SolarEclipseAnnular 日环食, annular solar eclipse.
|
||
SolarEclipseAnnular SolarEclipseType = "annular"
|
||
// SolarEclipseTotal 日全食, total solar eclipse.
|
||
SolarEclipseTotal SolarEclipseType = "total"
|
||
// SolarEclipseHybrid 全环食, hybrid solar eclipse.
|
||
SolarEclipseHybrid SolarEclipseType = "hybrid"
|
||
)
|
||
|
||
// SolarEclipseCentrality 中心线进入地球的方式, global eclipse centrality.
|
||
type SolarEclipseCentrality string
|
||
|
||
const (
|
||
// SolarEclipseNonCentral 非中心食, non-central eclipse.
|
||
SolarEclipseNonCentral SolarEclipseCentrality = "non_central"
|
||
// SolarEclipseCentralOneLimit 单界中心食, central eclipse with one limit.
|
||
SolarEclipseCentralOneLimit SolarEclipseCentrality = "central_one_limit"
|
||
// SolarEclipseCentralTwoLimits 双界中心食, central eclipse with two limits.
|
||
SolarEclipseCentralTwoLimits SolarEclipseCentrality = "central_two_limits"
|
||
)
|
||
|
||
// SolarEclipseInfo 全局日食信息, global solar eclipse information.
|
||
//
|
||
// 所有时刻字段都保持用户输入的时区。
|
||
// 不存在的阶段使用零值 time.Time。
|
||
type SolarEclipseInfo struct {
|
||
// Model 日食月亮半径模型, eclipse lunar radius model.
|
||
Model SolarEclipseRadiusModel
|
||
// Type 全局食型, global eclipse type.
|
||
Type SolarEclipseType
|
||
// Centrality 中心性, eclipse centrality.
|
||
Centrality SolarEclipseCentrality
|
||
// HasSaros 存在沙罗序列信息（可能是锚点外推结果）, has Saros series metadata (possibly extrapolated).
|
||
HasSaros bool
|
||
// Saros 是沙罗序列信息，包括系列号、系列内序号和总成员数。
|
||
// Saros is Saros series metadata with the series number, member index, and total member count.
|
||
Saros SarosInfo
|
||
|
||
// GreatestEclipse 食甚时刻, greatest eclipse.
|
||
GreatestEclipse time.Time
|
||
// PartialBeginOnEarth 地球范围偏食始, partial eclipse begins on Earth.
|
||
PartialBeginOnEarth time.Time
|
||
// PartialEndOnEarth 地球范围偏食终, partial eclipse ends on Earth.
|
||
PartialEndOnEarth time.Time
|
||
// CentralBeginOnEarth 地球范围中心食始, central eclipse begins on Earth.
|
||
CentralBeginOnEarth time.Time
|
||
// CentralEndOnEarth 地球范围中心食终, central eclipse ends on Earth.
|
||
CentralEndOnEarth time.Time
|
||
|
||
// Magnitude 全局食分, global eclipse magnitude.
|
||
Magnitude float64
|
||
// Gamma 食甚时影轴到地心的距离, gamma at greatest eclipse.
|
||
Gamma float64
|
||
// CentralDuration 是食甚点的中心食持续时间，即日食目录（如 NASA「Central Dur.」）
|
||
// 的取值口径；沿整条中心线的最大值见 SolarEclipsePath.MaxCentralDuration。
|
||
// CentralDuration is the central-phase duration at the greatest eclipse, the
|
||
// value catalogues publish; SolarEclipsePath.MaxCentralDuration is the maximum
|
||
// along the whole track.
|
||
CentralDuration time.Duration
|
||
// PathWidthKM 食甚处中心食带宽度, central path width at greatest eclipse.
|
||
PathWidthKM float64
|
||
|
||
// GreatestLongitude 食甚点经度，东正西负, longitude of greatest eclipse, east positive.
|
||
GreatestLongitude float64
|
||
// GreatestLatitude 食甚点纬度，北正南负, latitude of greatest eclipse, north positive.
|
||
GreatestLatitude float64
|
||
|
||
// HasPartial 存在偏食阶段, has partial phase.
|
||
HasPartial bool
|
||
// HasCentral 存在中心食阶段, has central phase.
|
||
HasCentral bool
|
||
// HasAnnular 存在环食阶段, has annular phase.
|
||
HasAnnular bool
|
||
// HasTotal 存在全食阶段, has total phase.
|
||
HasTotal bool
|
||
// HasHybrid 为混合食, is hybrid eclipse.
|
||
HasHybrid bool
|
||
}
|
||
|
||
// SolarEclipseOnDate 当地自然日全局日食查询 / local-date global solar eclipse query.
|
||
// Determine whether a global solar eclipse overlaps the local date, using NASA bulletin Split-K by default.
|
||
func SolarEclipseOnDate(date time.Time) (SolarEclipseInfo, bool) {
|
||
return SolarEclipseOnDateNASABulletinSplitK(date)
|
||
}
|
||
|
||
// SolarEclipseOnDateNASABulletinSplitK 当地自然日全局日食查询（NASA bulletin Split-K） / local-date global solar eclipse query with NASA bulletin Split-K.
|
||
// Determine whether a global solar eclipse overlaps the local date with the NASA bulletin Split-K model.
|
||
func SolarEclipseOnDateNASABulletinSplitK(date time.Time) (SolarEclipseInfo, bool) {
|
||
return solarEclipseOnDate(date, basic.SolarEclipseNASABulletinSplitK)
|
||
}
|
||
|
||
// SolarEclipseOnDateIAUSingleK 当地自然日全局日食查询（IAU Single-K） / local-date global solar eclipse query with IAU Single-K.
|
||
// Determine whether a global solar eclipse overlaps the local date with the IAU Single-K model.
|
||
func SolarEclipseOnDateIAUSingleK(date time.Time) (SolarEclipseInfo, bool) {
|
||
return solarEclipseOnDate(date, basic.SolarEclipseIAUSingleK)
|
||
}
|
||
|
||
func solarEclipseOnDate(date time.Time, calculator solarEclipseCalculator) (SolarEclipseInfo, bool) {
|
||
location := date.Location()
|
||
dayStart, dayMid, dayEnd := solarEclipseLocalDayBounds(date)
|
||
|
||
candidateTT := basic.CalcMoonSHByJDE(solarEclipseTimeToTTJDE(dayMid), 0)
|
||
result := calculator(candidateTT)
|
||
if result.Type == basic.SolarEclipseNone {
|
||
return SolarEclipseInfo{}, false
|
||
}
|
||
|
||
info := solarEclipseInfoFromBasic(result, location)
|
||
if !solarEclipseOverlapsDate(info, dayStart, dayEnd) {
|
||
return SolarEclipseInfo{}, false
|
||
}
|
||
return info, true
|
||
}
|
||
|
||
// LastSolarEclipse 上次日食 / previous solar eclipse.
|
||
// Previous solar eclipse, using NASA bulletin Split-K by default.
|
||
func LastSolarEclipse(date time.Time) SolarEclipseInfo {
|
||
return LastSolarEclipseNASABulletinSplitK(date)
|
||
}
|
||
|
||
// LastSolarEclipseNASABulletinSplitK 上次日食（NASA bulletin Split-K） / previous solar eclipse with NASA bulletin Split-K.
|
||
// Previous solar eclipse with the NASA bulletin Split-K model.
|
||
func LastSolarEclipseNASABulletinSplitK(date time.Time) SolarEclipseInfo {
|
||
info, _ := searchSolarEclipse(date, -1, true, basic.SolarEclipseNASABulletinSplitK)
|
||
return info
|
||
}
|
||
|
||
// LastSolarEclipseIAUSingleK 上次日食（IAU Single-K） / previous solar eclipse with IAU Single-K.
|
||
// Previous solar eclipse with the IAU Single-K model.
|
||
func LastSolarEclipseIAUSingleK(date time.Time) SolarEclipseInfo {
|
||
info, _ := searchSolarEclipse(date, -1, true, basic.SolarEclipseIAUSingleK)
|
||
return info
|
||
}
|
||
|
||
// NextSolarEclipse 下次日食 / next solar eclipse.
|
||
// Next solar eclipse, using NASA bulletin Split-K by default.
|
||
func NextSolarEclipse(date time.Time) SolarEclipseInfo {
|
||
return NextSolarEclipseNASABulletinSplitK(date)
|
||
}
|
||
|
||
// NextSolarEclipseNASABulletinSplitK 下次日食（NASA bulletin Split-K） / next solar eclipse with NASA bulletin Split-K.
|
||
// Next solar eclipse with the NASA bulletin Split-K model.
|
||
func NextSolarEclipseNASABulletinSplitK(date time.Time) SolarEclipseInfo {
|
||
info, _ := searchSolarEclipse(date, 1, false, basic.SolarEclipseNASABulletinSplitK)
|
||
return info
|
||
}
|
||
|
||
// NextSolarEclipseIAUSingleK 下次日食（IAU Single-K） / next solar eclipse with IAU Single-K.
|
||
// Next solar eclipse with the IAU Single-K model.
|
||
func NextSolarEclipseIAUSingleK(date time.Time) SolarEclipseInfo {
|
||
info, _ := searchSolarEclipse(date, 1, false, basic.SolarEclipseIAUSingleK)
|
||
return info
|
||
}
|
||
|
||
// ClosestSolarEclipse 最近一次日食 / closest solar eclipse.
|
||
// Closest solar eclipse, using NASA bulletin Split-K by default.
|
||
func ClosestSolarEclipse(date time.Time) SolarEclipseInfo {
|
||
return ClosestSolarEclipseNASABulletinSplitK(date)
|
||
}
|
||
|
||
// ClosestSolarEclipseNASABulletinSplitK 最近一次日食（NASA bulletin Split-K） / closest solar eclipse with NASA bulletin Split-K.
|
||
// Closest solar eclipse with the NASA bulletin Split-K model.
|
||
func ClosestSolarEclipseNASABulletinSplitK(date time.Time) SolarEclipseInfo {
|
||
last, hasLast := searchSolarEclipse(date, -1, true, basic.SolarEclipseNASABulletinSplitK)
|
||
next, hasNext := searchSolarEclipse(date, 1, false, basic.SolarEclipseNASABulletinSplitK)
|
||
return closestSolarEclipse(date, last, hasLast, next, hasNext)
|
||
}
|
||
|
||
// ClosestSolarEclipseIAUSingleK 最近一次日食（IAU Single-K） / closest solar eclipse with IAU Single-K.
|
||
// Closest solar eclipse with the IAU Single-K model.
|
||
func ClosestSolarEclipseIAUSingleK(date time.Time) SolarEclipseInfo {
|
||
last, hasLast := searchSolarEclipse(date, -1, true, basic.SolarEclipseIAUSingleK)
|
||
next, hasNext := searchSolarEclipse(date, 1, false, basic.SolarEclipseIAUSingleK)
|
||
return closestSolarEclipse(date, last, hasLast, next, hasNext)
|
||
}
|
||
|
||
func closestSolarEclipse(
|
||
date time.Time,
|
||
last SolarEclipseInfo,
|
||
hasLast bool,
|
||
next SolarEclipseInfo,
|
||
hasNext bool,
|
||
) SolarEclipseInfo {
|
||
switch {
|
||
case hasLast && !hasNext:
|
||
return last
|
||
case !hasLast && hasNext:
|
||
return next
|
||
case !hasLast && !hasNext:
|
||
return SolarEclipseInfo{}
|
||
}
|
||
|
||
lastDistance := math.Abs(date.Sub(last.GreatestEclipse).Seconds())
|
||
nextDistance := math.Abs(next.GreatestEclipse.Sub(date).Seconds())
|
||
if lastDistance <= nextDistance {
|
||
return last
|
||
}
|
||
return next
|
||
}
|
||
|
||
func searchSolarEclipse(
|
||
date time.Time,
|
||
direction int,
|
||
includeCurrent bool,
|
||
calculator solarEclipseCalculator,
|
||
) (SolarEclipseInfo, bool) {
|
||
targetTT := solarEclipseTimeToTTJDE(date)
|
||
candidateTT := basic.CalcMoonSHByJDE(targetTT, 0)
|
||
|
||
for i := 0; i < solarEclipseSearchLimit; i++ {
|
||
if isPotentialSolarEclipse(candidateTT) {
|
||
result := calculator(candidateTT)
|
||
if result.Type != basic.SolarEclipseNone && solarEclipseMatchesDirection(result.GreatestEclipse, targetTT, direction, includeCurrent) {
|
||
return solarEclipseInfoFromBasic(result, date.Location()), true
|
||
}
|
||
}
|
||
candidateTT = nextEclipseSearchCandidateTT(candidateTT, 0, direction, solarEclipseSynodicMonthDays)
|
||
}
|
||
|
||
return SolarEclipseInfo{}, false
|
||
}
|
||
|
||
func isPotentialSolarEclipse(newMoonTT float64) bool {
|
||
return math.Abs(basic.HMoonTrueBo(newMoonTT)) <= solarEclipseLatitudeLimitDeg
|
||
}
|
||
|
||
func solarEclipseMatchesDirection(greatestTT, targetTT float64, direction int, includeCurrent bool) bool {
|
||
delta := greatestTT - targetTT
|
||
if math.Abs(delta) <= solarEclipseSearchEpsilonDay {
|
||
return direction < 0 && includeCurrent
|
||
}
|
||
if direction > 0 {
|
||
return delta > 0
|
||
}
|
||
return delta < 0
|
||
}
|
||
|
||
func solarEclipseLocalDayBounds(date time.Time) (time.Time, time.Time, time.Time) {
|
||
location := date.Location()
|
||
dayStart := time.Date(date.Year(), date.Month(), date.Day(), 0, 0, 0, 0, location)
|
||
dayMid := time.Date(date.Year(), date.Month(), date.Day(), 12, 0, 0, 0, location)
|
||
dayEnd := time.Date(date.Year(), date.Month(), date.Day()+1, 0, 0, 0, 0, location)
|
||
return dayStart, dayMid, dayEnd
|
||
}
|
||
|
||
func nextSolarEclipseLocalDayStart(dayStart time.Time) time.Time {
|
||
location := dayStart.Location()
|
||
return time.Date(dayStart.Year(), dayStart.Month(), dayStart.Day()+1, 0, 0, 0, 0, location)
|
||
}
|
||
|
||
func solarEclipseInfoFromBasic(result basic.SolarEclipseResult, location *time.Location) SolarEclipseInfo {
|
||
saros, hasSaros := solarSarosInfo(result.GreatestEclipse)
|
||
return SolarEclipseInfo{
|
||
Model: mapBasicSolarEclipseModel(result.Model),
|
||
Type: mapBasicSolarEclipseType(result.Type),
|
||
Centrality: mapBasicSolarEclipseCentrality(result.Centrality),
|
||
HasSaros: hasSaros,
|
||
Saros: saros,
|
||
GreatestEclipse: solarEclipseTTJDEToTime(result.GreatestEclipse, location),
|
||
PartialBeginOnEarth: solarEclipseTTJDEToTime(result.PartialBeginOnEarth, location),
|
||
PartialEndOnEarth: solarEclipseTTJDEToTime(result.PartialEndOnEarth, location),
|
||
CentralBeginOnEarth: solarEclipseTTJDEToTime(result.CentralBeginOnEarth, location),
|
||
CentralEndOnEarth: solarEclipseTTJDEToTime(result.CentralEndOnEarth, location),
|
||
Magnitude: result.Magnitude,
|
||
Gamma: result.Gamma,
|
||
CentralDuration: solarEclipseDurationFromDays(result.CentralDurationDays),
|
||
PathWidthKM: result.PathWidthKM,
|
||
GreatestLongitude: result.GreatestLongitude,
|
||
GreatestLatitude: result.GreatestLatitude,
|
||
HasPartial: result.HasPartial,
|
||
HasCentral: result.HasCentral,
|
||
HasAnnular: result.HasAnnular,
|
||
HasTotal: result.HasTotal,
|
||
HasHybrid: result.HasHybrid,
|
||
}
|
||
}
|
||
|
||
func mapBasicSolarEclipseModel(model basic.SolarEclipseRadiusModel) SolarEclipseRadiusModel {
|
||
switch model {
|
||
case basic.SolarEclipseModelIAUSingleK:
|
||
return SolarEclipseModelIAUSingleK
|
||
default:
|
||
return SolarEclipseModelNASABulletinSplitK
|
||
}
|
||
}
|
||
|
||
func mapBasicSolarEclipseType(eclipseType basic.SolarEclipseType) SolarEclipseType {
|
||
switch eclipseType {
|
||
case basic.SolarEclipsePartial:
|
||
return SolarEclipsePartial
|
||
case basic.SolarEclipseAnnular:
|
||
return SolarEclipseAnnular
|
||
case basic.SolarEclipseTotal:
|
||
return SolarEclipseTotal
|
||
case basic.SolarEclipseHybrid:
|
||
return SolarEclipseHybrid
|
||
default:
|
||
return SolarEclipseNone
|
||
}
|
||
}
|
||
|
||
func mapBasicSolarEclipseCentrality(centrality basic.SolarEclipseCentrality) SolarEclipseCentrality {
|
||
switch centrality {
|
||
case basic.SolarEclipseCentralOneLimit:
|
||
return SolarEclipseCentralOneLimit
|
||
case basic.SolarEclipseCentralTwoLimits:
|
||
return SolarEclipseCentralTwoLimits
|
||
default:
|
||
return SolarEclipseNonCentral
|
||
}
|
||
}
|
||
|
||
func solarEclipseOverlapsDate(info SolarEclipseInfo, dayStart, dayEnd time.Time) bool {
|
||
eventStart, eventEnd, ok := solarEclipseRange(info)
|
||
if !ok {
|
||
return false
|
||
}
|
||
return !eventEnd.Before(dayStart) && eventStart.Before(dayEnd)
|
||
}
|
||
|
||
func solarEclipseRange(info SolarEclipseInfo) (time.Time, time.Time, bool) {
|
||
if !info.HasPartial {
|
||
return time.Time{}, time.Time{}, false
|
||
}
|
||
return info.PartialBeginOnEarth, info.PartialEndOnEarth, true
|
||
}
|
||
|
||
func solarEclipseTTJDEToTime(ttJDE float64, location *time.Location) time.Time {
|
||
return solarEclipseTTJDEToTimeWithDeltaT(ttJDE, basic.DeltaT(ttJDE, true), location)
|
||
}
|
||
|
||
// solarEclipseTTJDEToTimeWithDeltaT 用显式 ΔT 把 TT 换算为时刻：显式 ΔT 的单时刻入口
|
||
// 必须走这条路径，否则回填出来的 UT 会落到进程级模型上，与几何使用的 ΔT 不一致。
|
||
// solarEclipseTTJDEToTimeWithDeltaT converts TT with an explicit ΔT; the single-instant
|
||
// entries must use it so the reported UT matches the ΔT their geometry used.
|
||
func solarEclipseTTJDEToTimeWithDeltaT(
|
||
ttJDE, deltaTSeconds float64, location *time.Location,
|
||
) time.Time {
|
||
// 与 lunar 侧一致：0 与 NaN/±Inf 都表示“该时刻不存在”。
|
||
if ttJDE == 0 || math.IsNaN(ttJDE) || math.IsInf(ttJDE, 0) {
|
||
return time.Time{}
|
||
}
|
||
utcJDE := ttJDE - deltaTSeconds/86400
|
||
return basic.JDE2DateByZone(utcJDE, location, false)
|
||
}
|
||
|
||
func solarEclipseTimeToTTJDE(date time.Time) float64 {
|
||
utcJDE := basic.Date2JDE(date.UTC())
|
||
return basic.TD2UT(utcJDE, true)
|
||
}
|