@kuntay/swisseph-asteroids

Ephemeris files for 16 popular asteroids and dwarf planets — the optional asteroid companion to @kuntay/swisseph.

409 KB. Covers 1500–2100 CE.

License: AGPL-3.0-or-later. See NOTICE.

Contents

| Body | MPC # | | Body | MPC # | |---|---|---|---|---| | Astraea | 5 | | Ixion | 28978 | | Hygiea | 10 | | Quaoar | 50000 | | Psyche | 16 | | Sedna | 90377 | | Eros | 433 | | Orcus | 90482 | | Lilith (asteroid) | 1181 | | Haumea | 136108 | | Nessus | 7066 | | Eris | 136199 | | Chariklo | 10199 | | Makemake | 136472 | | Varuna | 20000 | | Gonggong | 225088 |

Ceres, Pallas, Juno, Vesta, Chiron and Pholus are not here — they already live in the main ephemeris (seas_18.se1) that ships with @kuntay/swisseph-data.

Usage

import { createSwissEph, Asteroid, asteroidBody } from '@kuntay/swisseph';

const swe = await createSwissEph();
// ... mount the main ephemeris and this package's ephe/ directory ...

const eris = swe.calc(jd, asteroidBody(Asteroid.Eris));

Always go through asteroidBody() rather than AsteroidOffset + number. Swiss Ephemeris only remaps MPC numbers 1–4 to its built-in bodies, so AsteroidOffset + 2060 looks for a se02060s.se1 file and throws, even though Chiron is present in the main ephemeris. asteroidBody() resolves the six built-in bodies to their Body constants and everything else to the offset.

Two behaviours that differ from planets

Missing files are hard errors. Planets silently fall back to the built-in Moshier theory when a file is absent. Asteroids have no analytic theory, so a missing file throws. Catch it.

Coverage is narrower. These are the short files: 1500–2100 CE. Long versions covering 3000 BCE – 2999 CE exist upstream but are roughly 10× larger (Eros: 92 KB short, 914 KB long).

Provenance

Files are fetched from the HTTP mirror listed in the upstream readme (https://ephe.scryr.io/ephe, provided by Phillip McCabe) and verified to carry a valid .se1 header. manifest.json records the SHA-256 of every file.

Data produced by Astrodienst AG from NASA/JPL Development Ephemeris DE441. Upstream: https://github.com/aloistr/swisseph