greenwichSiderealTimefunction

The Greenwich mean sidereal time: how far the Earth has turned against the stars, as the right ascension on the meridian of Greenwich, in degrees (Meeus 12.4, the IAU 1982 expression). It uses UT, which is UTC to under a second, and is the mean time, without the nutation term (at most about 1.1 seconds of time, 17 arc-seconds).

import { greenwichSiderealTime } from "@johnmorrisdotca/hoshi-stars/sky";

function greenwichSiderealTime(when: When): number

import { greenwichSiderealTime } from "@johnmorrisdotca/hoshi-stars/sky";

// Meeus example 12.a: 1987 April 10 at 0h UT is 13h10m46.3668s, 197.693195 degrees
console.log(greenwichSiderealTime(Date.UTC(1987, 3, 10)).toFixed(6));

197.693195