An existing product called PG Orbit (a mobile PostgreSQL client)
creates a naming conflict. pg_orrery — a database orrery built from
Keplerian parameters and SQL instead of brass gears.
Build system: control file, Makefile, Dockerfile, docker init script.
C source: GUC prefix, PG_FUNCTION_INFO_V1 symbol, header guards,
ereport prefixes, comments across ~30 files including vendored SGP4.
SQL: all 5 install/migration scripts, function name pg_orrery_ephemeris_info.
Tests: 9 SQL suites, 8 expected outputs, standalone DE reader test.
Documentation: CLAUDE.md, README.md, DESIGN.md, Starlight site infra,
36 MDX pages, OG renderer, logo SVG, docker-compose, agent threads.
All 13 regression suites pass. Docs site builds (37 pages).
Clean-room DE binary reader (~400 lines C) with Chebyshev/Clenshaw
evaluation — no GPL dependency on jpl_eph. Per-backend lazy
initialization preserves PARALLEL SAFE. Existing VSOP87/ELP82B
functions stay IMMUTABLE; new _de() variants are STABLE with
automatic fallback to compiled-in ephemerides on any DE failure.
Implementation:
- de_reader.c: header parse, record seek, Clenshaw recurrence
- eph_provider.c: GUC (pg_orbit.ephemeris_path), lazy init,
ICRS-to-ecliptic frame rotation, on_proc_exit cleanup
- de_funcs.c: 11 new SQL functions (_de variants + diagnostics)
- Constant chain of custody rules 6-8 (frame rotation,
same-provider, AU consistency)
Extract observe_from_geocentric() to astro_math.h for shared use
by planet_funcs.c, moon_funcs.c, and de_funcs.c.
57 → 68 functions, 11 → 12 regression test suites, all passing.
Phase 1 — Stars, comets, Keplerian propagation:
- star_observe() / star_observe_safe(): fixed star alt/az via IAU 1976
precession, equatorial-to-horizontal transform
- kepler_propagate(): two-body Keplerian orbit propagation for
elliptic, parabolic, and hyperbolic orbits
- comet_observe(): observe comets/asteroids from orbital elements
- heliocentric type: ecliptic J2000 position (x, y, z in AU)
Phase 2 — VSOP87 planets, ELP82B Moon, Sun:
- planet_heliocentric(): VSOP87 heliocentric ecliptic J2000 positions
for Mercury through Neptune (Bretagnon & Francou, MIT)
- planet_observe(): full observation pipeline for any planet
- sun_observe(): Sun position from negated Earth VSOP87
- moon_observe(): ELP2000-82B lunar position (Chapront-Touzé, MIT)
- Clean-room precession (IAU 2006) and sidereal time (IERS 2010)
- elliptic_to_rectangular utility (Stellarium, MIT)
All Stellarium extractions are MIT-licensed, thread-safe (static
caching removed for PARALLEL SAFE), zero external data files.
All 9 regression tests pass (90ms total).
