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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 · How big a Messier object is on the sky and which way it lies, and its outline

deepSkyOutlinefunction

The outline of an object on the sky: a closed ring of points (the first repeated as the last) round an ellipse of the shape's major and minor axes at its angle. Where the minor axis or the angle is not known the ring is a circle of the major diameter, because no other shape is measured. The points are on the sky, so any projection can draw them.

Import it

import { deepSkyOutline } from "@johnmorrisdotca/hoshi-stars/deep-sky/shape";

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

Definition

function deepSkyOutline(centre: SkyPoint, shape: DeepSkyShape, points?: number): SkyPoint[] | undefined

Parameters

NameTypeDescription
centreSkyPoint

The object's position.

shapeDeepSkyShape

Its shape, from deepSkyShape.

points (optional)number

How many points round it, at least 8 (default 48).

Returns

SkyPoint[] | undefined

The ring, or undefined where the shape has no size.

Examples

import { deepSkyObject } from "@johnmorrisdotca/hoshi-stars/deep-sky";
import { deepSkyOutline, deepSkyShape } from "@johnmorrisdotca/hoshi-stars/deep-sky/shape";

const m31 = deepSkyObject("M31")!;
console.log(deepSkyOutline(m31, deepSkyShape(m31), 16)!.length);
17

What it prints (run when this page was built)

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