@jauza/jpl-de

JPL DE Sun and Moon positions exposed as a Jauza algorithm adapter. The package uses CSPICE and downloads the selected DE slim kernel and naif0012.tls from the Jauza release CDN at runtime.

Usage

import { jplDe } from "@jauza/jpl-de";

const algorithm = jplDe.load("de440-slim");
await jplDe.ready;

const sun = algorithm.SUN!.formula({ jd: 2448908.5 });

The returned coordinates are geometric equatorial J2000 right ascension and declination, with distances in kilometres. Use the adapter with @jauza/core for frame conversion and observer calculations.

The adapter also publishes a dedicated apparent source computed with CSPICE CN+S (converged Newtonian light-time plus stellar aberration). Through @jauza/core, geometric() reads the geometric NONE state while the apparent accessors (ra, dec, lambda, beta) and topocentric alt/az/horizontal read the CN+S state. Apparent results exclude gravitational light deflection and atmospheric refraction.

Supported series are de421-slim, de430-slim, de435-slim, de440-slim, de440s-slim, and de442-slim. Only one series can be initialized per process; calling load() with a different series after initialization throws an error.

The DE440 ephemeris covers approximately 1550 through 2650. UTC conversion is limited by the configured naif0012.tls leap-second data and does not account for leap seconds after 2016-12-31. Future UTC dates therefore require updated leap-second data for accurate time conversion.

Requirements

• @jauza/core 0.1.x
• A runtime with fetch