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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

Startype

One star, as the Yale Bright Star Catalogue gives it. Positions are J2000 (equator and equinox of 2000, the FK5 frame, which is the ICRS to a fraction of an arc-second).

Import it

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

Definition

interface Star {
    hr: number;
    name: string | undefined;
    nameJa: string | undefined;
    designation: string | undefined;
    constellation: string;
    rightAscension: number;
    declination: number;
    magnitude: number;
    colourIndex: number | undefined;
    spectralClass: string;
    properMotionRaMas: number;
    properMotionDecMas: number;
    parallaxMas: number;
}

Members

NameTypeDescription
hrnumber

The Bright Star Catalogue (Harvard Revised) number: stable, and the key for starByHr.

namestring | undefined

The common name where the star has one (the IAU Working Group on Star Names' spelling), else undefined.

nameJastring | undefined

The name in katakana (シリウス) for every star that has a name, else undefined.

designationstring | undefined

The Bayer letter and constellation (α CMa), else the Flamsteed number and constellation (9 CMa), else undefined.

constellationstring

The IAU three-letter constellation abbreviation (CMa) the star lies in, for every star: the catalogue's where the star has a Bayer letter or Flamsteed number, else the one the boundaries give.

rightAscensionnumber

Right ascension in degrees at J2000, 0 up to 360. The catalogue gives it to a tenth of a second of time (1.5 arc-seconds at the equator).

declinationnumber

Declination in degrees at J2000, -90 to 90. The catalogue gives it to an arc-second.

magnitudenumber

Visual magnitude: smaller is brighter, and Sirius is -1.46.

colourIndexnumber | undefined

The colour index B-V in magnitudes, or undefined where the catalogue has none. Hot blue stars are about -0.3, the Sun 0.65, cool red stars above 1.5.

spectralClassstring

The spectral class and subclass (A1, K1), or an empty string where the catalogue gives none we read.

properMotionRaMasnumber

Proper motion in right ascension, in milliarcseconds a year, already multiplied by cos(declination) (a true angle on the sky).

properMotionDecMasnumber

Proper motion in declination, in milliarcseconds a year.

parallaxMasnumber

The annual parallax in milliarcseconds; 0 where the catalogue has none (the distance is then unknown).

Examples

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

const sirius: Star = starByName("Sirius")!;
console.log(sirius.designation, sirius.magnitude);
α CMa -1.46

What it prints (run when this page was built)

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