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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 · Pictures of deep-sky objects and where each lies on the sky

DeepSkyPicturetype

A picture of one deep-sky object. It is a tangent-plane image about its centre with north at the top and east on the left (the way sky photographs are), turned by rotation, so its place on the sky is exact and pictureCorners gives its corners.

Import it

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

Definition

interface DeepSkyPicture {
    id: string;
    object: string;
    file: string;
    width: number;
    height: number;
    centre: SkyPoint;
    arcsecPerPixel: number;
    rotation: number;
    source: PictureSource;
    credit: string;
    address: string;
}

Members

NameTypeDescription
idstring

The picture's own id: the object's id (M31) for the survey picture, which is the widest view, and the object's id and the release (M51-heic0506a) for a finer picture of part of it. Unique.

objectstring

The id of the deep-sky object the picture shows (M31), the same as DeepSkyObject.id.

filestring

The file's path under the folder the pictures are served from, pictures/M31.webp (the files are in the repository's pictures/ and on the demo site, not in the npm package); it is a WebP image with transparency, so laid over a dark sky it adds light and no rectangle.

widthnumber

Width in pixels.

heightnumber

Height in pixels.

centreSkyPoint

The sky point at the middle of the picture (J2000, degrees).

arcsecPerPixelnumber

The angular size of a pixel in arc-seconds.

rotationnumber

Degrees the picture's top is turned from north toward east; 0 for north up.

sourcePictureSource

Where the picture comes from.

creditstring

The credit line for this picture: the survey's, or the release's own for a picture from a space agency.

addressstring

Where the picture was read from: the SkyView address the first band was cut from (the one that says exactly what was asked), or the page of the release.

Examples

import { deepSkyPicture, type DeepSkyPicture } from "@johnmorrisdotca/hoshi-stars/deep-sky/pictures";

const picture: DeepSkyPicture = deepSkyPicture("M31")!;
console.log(picture.file, picture.width, picture.arcsecPerPixel);
pictures/M31.webp 1800 7.25

What it prints (run when this page was built)

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