21 lines
875 B
Go
21 lines
875 B
Go
package orbit
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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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// ParallacticAngle 轨道目标视差角（天顶方向角） / orbit-target parallactic angle.
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//
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// 返回轨道目标在观测者所在地的视差角，单位度；`observerLon` 东经为正，`observerLat` 北纬为正，`observerHeight` 单位米。
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// Returns the parallactic angle of the orbital target for the observing site, in degrees. `observerLon` is east-positive, `observerLat` is north-positive, and `observerHeight` is in meters.
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func ParallacticAngle(date time.Time, elements Elements, observerLon, observerLat, observerHeight float64) float64 {
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position := ApparentTopocentricEquatorial(date, elements, observerLon, observerLat, observerHeight)
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return basic.ParallacticAngleByHourAngle(
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HourAngle(date, elements, observerLon, observerLat, observerHeight),
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position.Dec,
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observerLat,
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)
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}
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