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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 · What you can see tonight: the stars above the horizon of a place and a moment that the Sun's light, the sky's darkness and the air still let through, with the twilight, each star's altitude and azimuth and how easy it is to see

airmassfunction

The airmass of the line of sight at an altitude, by Kasten and Young (1989): 1 at the zenith, 2 at 30 degrees, about 38 at the horizon. Good to the horizon, which a plane-parallel secant is not.

Import it

import { airmass } from "@johnmorrisdotca/hoshi-stars/tonight";

Definition

function airmass(altitude: number): number

Parameters

NameTypeDescription
altitudenumber

Degrees above the horizon, 0 to 90.

Returns

number

The airmass.

Examples

import { airmass } from "@johnmorrisdotca/hoshi-stars/tonight";

console.log(airmass(90).toFixed(1), airmass(30).toFixed(1)); // 1.0 2.0
1.0 2.0

What it prints (run when this page was built)

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