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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 · A constellation in 3D: its stars placed in space from their parallaxes, with the range each error allows and the Earth's lines of sight

StarIn3Dtype

One star of a figure in space, as seen from the viewpoint (the Earth, or another star).

Import it

import type { StarIn3D } from "@johnmorrisdotca/hoshi-stars/constellation-3d";

Definition

interface StarIn3D {
    star: Star;
    id: string;
    quality: DistanceQuality;
    relativeError: number | undefined;
    sight: {
        origin: Point3;
        direction: Point3;
        near: number | undefined;
        best: number | undefined;
        far: number | undefined;
    };
    position: Point3 | undefined;
    nearPosition: Point3 | undefined;
    farPosition: Point3 | undefined;
    lightYears: number | undefined;
    range: readonly [
        near: number,
        far: number
    ] | undefined;
    wide: boolean;
}

Members

NameTypeDescription
starStar

The catalogue's star.

idstring

A key that stays the same: hr-2061.

qualityDistanceQuality

How well the distance is known.

relativeErrornumber | undefined

The parallax's error as a share of the parallax (0.05 is 5%), or undefined where the parallax has no stated error or there is no parallax.

sight{ origin: Point3; direction: Point3; near: number | undefined; best: number | undefined; far: number | undefined; }

The Earth's line of sight to the star: it starts at the Earth and runs along direction, and the star lies somewhere on it. The distances below are measured along it from the Earth (atLightYears).

positionPoint3 | undefined

The star's place: undefined for a star with no parallax, which is never put at a guessed distance.

nearPositionPoint3 | undefined

The nearest and the farthest place one standard error of the parallax allows; undefined where there is no error. The farthest is undefined too where the error reaches the parallax and the star could be any distance beyond.

farPositionPoint3 | undefined
lightYearsnumber | undefined

The distance from the viewpoint in light-years, or undefined where there is no parallax.

rangereadonly [near: number, far: number] | undefined

The nearest and farthest distance from the viewpoint within one standard error; undefined where there is no error. The farthest is Infinity where the error reaches the parallax.

wideboolean

True when the error bar is wider than the distance (the error is over 41% of the parallax, or reaches it): the star could be anywhere along a long stretch, so a picture shows the whole range and no point in the middle.

Examples

import { constellationIn3D, type StarIn3D } from "@johnmorrisdotca/hoshi-stars/constellation-3d";

const star: StarIn3D = constellationIn3D("Ori").stars[0]!;
console.log(star.id, star.quality);
hr-2061 fair

What it prints (run when this page was built)

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