starPosition関数
リファレンスの説明と例は英語です。見出しと目次は日本語です。
Where a star is at a moment: its J2000 position carried forward (or back) by its proper motion in a straight line. The frame stays J2000, so precession to the date is not applied: use
the result with J2000 coordinates, or convert it to the date with /coordinates. A straight line is good to a fraction of an arc-second for centuries for nearly every star here; it is
not good for the few with large motion over millennia.
インポート
import { starPosition } from "@johnmorrisdotca/hoshi-stars";定義
function starPosition(star: Pick<Star, "rightAscension" | "declination" | "properMotionRaMas" | "properMotionDecMas">, when?: When): { rightAscension: number; declination: number; }引数
| 名前 | 型 | 説明 |
|---|---|---|
star | Pick<Star, "rightAscension" | "declination" | "properMotionRaMas" | "properMotionDecMas"> | A star, or anything with a J2000 position and a proper motion in milliarcseconds a year (a nearby star from |
when (省略可) | When | undefined | The moment as a |
戻り値
{ rightAscension: number; declination: number; }
Right ascension and declination in degrees, J2000 frame, at that moment.
例
import { starByName, starPosition } from "@johnmorrisdotca/hoshi-stars";
const now = starPosition(starByName("Arcturus")!, Date.UTC(2026, 10, 7));
console.log(now.declination.toFixed(3));19.168出力（このページを作ったときに実行した結果）
この日本語は、まだ日本語を母語とする方の確認を受けていません。訂正を歓迎します。