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.
Reflects the full solar system expansion: 57 functions, 7 types,
11 test suites, 36 source files, body ID tables, error handling
patterns, astronomical constants, and the Starlight docs site.
6 custom types (tle, eci_position, geodetic, topocentric, observer,
pass_event), 67 SQL functions, 2 operators (&&, <->), and a GiST
operator class for altitude-band indexing. Wraps Bill Gray's sat_code
for SGP4/SDP4 propagation with WGS-72 constants for propagation and
WGS-84 for coordinate output. All 5 regression tests pass on PG 18.
