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Wakusei Planets惑星

The Sun, the planets and their moons as a clean line drawing, a shaded realistic drawing or a painted surface map, with real sizes, tilt and rotation, and the moons where they are at any date and time.

Wakusei is the Japanese word 惑星 for a planet. About the name

Contents

Reference · Julian dates (and the julian package's functions), calendars, time scales, sidereal time and Mars time

tdbMinusTtfunction

TDB minus TT in seconds: a term that follows the Earth round the Sun and is never more than 1.7 milliseconds (Meeus's two terms, 0.001657 sin g and 0.000014 sin 2g, good to about 30 microseconds).

Import it

import { tdbMinusTt } from "@johnmorrisdotca/wakusei-planets/time";

Definition

function tdbMinusTt(when: When): number

Parameters

NameTypeDescription
whenWhen

A Date or milliseconds since 1970 (read as TT).

Returns

number

Seconds.

Examples

import { tdbMinusTt } from "@johnmorrisdotca/wakusei-planets/time";

console.log(Math.abs(tdbMinusTt(Date.UTC(2026, 0, 3))) < 0.002);
true

What it prints (run when this page was built)

View sourceEdit on GitHubMade from the source of @johnmorrisdotca/wakusei-planets 0.24.0.