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Hoshi Stars星

The stars you can see without a telescope, with names, colours and distances; the 88 constellations with their lines and boundaries; the Messier objects; and seven map projections to draw them on.

Hoshi is the Japanese word 星 for a star. About the name

Contents

Reference · Your sky: altitude and azimuth for a place and a moment

localSiderealTimefunction

The local mean sidereal time: the right ascension that is on your meridian, due south or north of you, in degrees. A star with this right ascension is crossing the meridian.

Import it

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

Definition

function localSiderealTime(when: When, longitude: number): number

Parameters

NameTypeDescription
whenWhen

The moment, a Date or milliseconds since 1970.

longitudenumber

Degrees east of Greenwich (west is negative). Any finite number.

Returns

number

Degrees, 0 up to but not including 360.

Examples

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

// Greenwich's 197.693195 degrees at 0h UT, 1987 April 10, and Washington is 77.07 degrees west of it
console.log(localSiderealTime(Date.UTC(1987, 3, 10), -77.0656).toFixed(3)); // 120.628
120.628

What it prints (run when this page was built)

View sourceEdit on GitHubMade from the source of @johnmorrisdotca/hoshi-stars 0.7.0.