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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 · The Messier objects

GalaxyDistancetype

The distance to a galaxy, with what is known of where it came from. The headline is the median of the distances the source gives; no value is averaged with a different method's, because none states a method.

Import it

import type { GalaxyDistance } from "@johnmorrisdotca/hoshi-stars/deep-sky";

Also exported from: @johnmorrisdotca/hoshi-stars/deep-sky/ngc-ic

Definition

interface GalaxyDistance {
    lightYears: number;
    parsecs: number;
    error: DistanceValue | null;
    method: string;
    sources: GalaxyDistanceSource[];
    count: number;
    spread: {
        low: DistanceValue;
        high: DistanceValue;
    };
    disagree: boolean;
}

Members

NameTypeDescription
lightYearsnumber

The distance in light-years (the median of the statements).

parsecsnumber

The distance in parsecs (the median of the statements).

errorDistanceValue | null

The error, or null where no statement states one. It is the half-width of the bounds the source gives, not a total error: the values that disagree with each other (see spread) often differ by more.

methodstring

How the distance was measured. For every distance here it is "compiled, method not stated": the source gathers published values and names no method.

sourcesGalaxyDistanceSource[]

Where the values were read, for the credit line and the trace back.

countnumber

The number of statements the distance is the median of.

spread{ low: DistanceValue; high: DistanceValue; }

The lowest and highest of the statements. The same value twice where there is one statement.

disagreeboolean

True where the highest statement is more than 1.2 times the lowest: the sources disagree and the distance is good to less than the headline's digits.

Examples

import { deepSkyObject, galaxyDistance, type GalaxyDistance } from "@johnmorrisdotca/hoshi-stars/deep-sky";

const distance: GalaxyDistance | null = galaxyDistance(deepSkyObject("M31")!);
console.log(distance?.lightYears, distance?.method);
2674482.297277295 compiled, method not stated

What it prints (run when this page was built)

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