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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 · Stars: names, positions, distance and colour

absoluteMagnitudefunction

A star's absolute magnitude: how bright it would look from 10 parsecs (32.6 light-years), from its visual magnitude and its parallax (M = V + 5 + 5 log10(parallax in arc-seconds)). It is the brightness the Hertzsprung-Russell diagram plots against colour. The Sun is 4.83 and Sirius 1.45. The dimming of starlight by interstellar dust is not corrected, so a distant star is a little fainter than it is; the catalogue holds no figure for it.

Import it

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

Definition

function absoluteMagnitude(star: Pick<Star, "magnitude" | "parallaxMas">): number | undefined

Parameters

NameTypeDescription
starPick<Star, "magnitude" | "parallaxMas">

A star, or anything with a visual magnitude and a parallax in milliarcseconds.

Returns

number | undefined

The absolute magnitude, or undefined where there is no parallax (or a non-positive one). It carries the parallax's error: a star with a poor parallax has a poor absolute magnitude.

Examples

import { absoluteMagnitude, starByName } from "@johnmorrisdotca/hoshi-stars";

console.log(absoluteMagnitude(starByName("Sirius")!)?.toFixed(2));
1.45

What it prints (run when this page was built)

View sourceEdit on GitHubMade from the source of @johnmorrisdotca/hoshi-stars 0.47.0.