pleiades-data

Packaged offline ephemeris data (precomputed positions for the Sun, the Moon, Mercury through Pluto and the asteroid 433 Eros, derived from JPL public-domain ephemerides) and its EphemerisBackend for the pleiades astrology workspace.

The crate ships a compressed artifact covering 1900-01-01 through 2100-01-01, regenerated from the checked-in JPL reference snapshot and validated against a deterministic binary fixture. It covers the comparison-body planetary set plus the source-backed custom asteroid asteroid:433-Eros, and falls back to other providers when callers request bodies outside the packaged slice. Enable the packaged-artifact-path feature to load an explicit artifact file for larger or externally distributed packaged datasets.

Quick start

use pleiades_backend::{CelestialBody, Instant, JulianDay, TimeScale};
use pleiades_data::{packaged_backend, packaged_lookup};

let _backend = packaged_backend();
let instant = Instant::new(JulianDay::from_days(2_451_545.0), TimeScale::Tt);
let sun = packaged_lookup(&CelestialBody::Sun, instant)
    .expect("Sun should be in the packaged artifact");
assert!(sun.distance_au.is_some());

Besides the packaged bodies, the backend serves six derived lunar points: the osculating TrueNode, TrueApogee and TruePerigee (from the packaged Moon state) and the mean MeanNode, MeanApogee and MeanPerigee (from the mean lunar elements in pleiades-apsides). The mean apogee and perigee are the points on the inclined mean orbit, as Swiss Ephemeris reports SE_MEAN_APOG. All six are served only inside the packaged window.

Status

Experimental, pre-1.0: breaking changes can land in any minor release. This backend returns mean geometric coordinates and rejects apparent requests; the chart layer in pleiades-core and the event engines in pleiades-events apply apparent place on top of it. See the workspace README for the full maturity posture.

License

MIT OR Apache-2.0