pluto99 ♇

A fast implementation of the so-called pluto99 theory in JavaScript.

What?

A JavaScript library to get the heliocentric rectangular coordinates of dwarf planet Pluto, at mean equinox and ecliptic J2000, according to the so-called "pluto99" theory.

The JavaScript implementation is about 13.23 Kb (minified and gzipped).

The WebAssembly version is 26.17 Kb (minified and gzipped).

Install

$ yarn add pluto99

Usage

JavaScript version

In node:

const pluto99 = require('pluto99');

// Get an object with the (x,y,z) coordinates of Pluto.
const coords = pluto99(2451545);

In browsers, we recommend to load the script asynchronously:

import('pluto99').then((pluto99) => {
  // Get an object with the (x,y,z) coordinates of Pluto.
  const coords = pluto99(2451545);
});

WebAssembly version

In browsers:

import pluto99Loader from 'pluto99/dist/pluto99-wasm';

pluto99Loader.then((pluto99) => {
  // Get an object with the (x,y,z) coordinates of Pluto.
  const coords = pluto99(2451545);
});

About the precision

According to the doc:

The theory is valid between the years -2997 and 2983. (60 centuries approximately).

The largest discrepancy obtained by a comparison with the source DE406 is 0.00005 ua.

The largest discrepancies obtained in a comparison with the elements deduced from DE406 are:

• a : 0.080 au (semi-major axis)
• l : 0.2 degree (mean longitude)
• h,k : 0.0022 degree
• p,q : 0.0003 degree

Contribute

Build the JavaScript version

$ yarn build

Build the WebAssembly version

Install emscripten, then:

$ ./build && yarn build

Run the unit tests

Make sure to run the build script first, then:

$ yarn test

List of changes

With regards to the original terms, the following changes have been applied:

• Converted phi from degrees to radians
• Multiplied Nu by 1,000 for consistency with the VSOP87 theory

"So-called"?

The theory full name is "Pluto's tables from -2997 to 2983" and was published in March 1999.

Although, unlike VSOP, it does not have an official short name, it is popularly called "pluto99".