3 Commits

Author SHA1 Message Date
22b272fd0c Implement v0.17.0: solar elongation, planet phase, satellite eclipse, observing night quality, lunar libration
162 → 174 SQL objects, 27 → 28 test suites, 3 new C source files.

Features:
- solar_elongation(body_id, ts): Sun-Earth-Planet angle [0,180] degrees
- planet_phase(body_id, ts): illuminated disk fraction [0,1]
- satellite_is_eclipsed/next_eclipse_entry/exit/eclipse_fraction:
  cylindrical shadow model (Vallado §5.3) for Earth shadow prediction
- observing_night_quality(observer, ts): composite PL/pgSQL scoring
  based on astronomical darkness duration and Moon interference
- moon_libration_longitude/latitude/position_angle/libration/subsolar_longitude:
  optical libration from Meeus (1998) Ch. 53

Refactored magnitude_funcs.c to extract shared compute_planet_geometry()
used by magnitude, elongation, and phase — single VSOP87 evaluation per call.

All 28 regression suites pass. Zero compiler warnings.
2026-02-26 18:47:30 -07:00
9949af738d Fix planet_magnitude: use full Mallama & Hilton (2018) polynomials
The original implementation only used c1+c2 coefficients from the
simplified model. Mercury's 6th-order polynomial diverges badly
beyond ~60 deg phase angle with only 2 terms — returning -23 mag
at 130 deg (should be +1.1).

Now uses the complete piecewise models from the paper:
- Mercury: full 6th-order polynomial (Eq. 1)
- Venus: piecewise at 163.7 deg (Eq. 2/3)
- Mars: piecewise at 50 deg (Eq. 5/6)
- Jupiter: piecewise at 12 deg with log term (Eq. 7/8)
- Saturn: globe-only model (Eq. 11/12), ring tilt still not modeled
- Uranus: phase threshold at 3.1 deg (Eq. 14)
- Neptune: phase threshold at 1.9 deg (Eq. 17)

Bug found by astrolock: Mercury at superior conjunction (i=130.6 deg)
returned -23.3 mag instead of +1.1.
2026-02-26 17:23:44 -07:00
46c8a30575 Add v0.16.0: twilight dawn/dusk, lunar phase, planet apparent magnitude
Twilight: 6 functions (civil/nautical/astronomical × dawn/dusk) reusing
the existing find_next_crossing() bisection search with Sun depression
angle thresholds (-6°, -12°, -18°). Returns NULL for polar regions
where the threshold is never reached.

Lunar phase: 4 functions computing Sun-Earth-Moon geometry from VSOP87
+ ELP2000-82B. Phase angle [0,360) via elongation + cross product
z-component for waxing/waning discrimination. 8 named phases in 45°
bins. Moon age approximated from phase angle and mean synodic month.

Planet magnitude: Mallama & Hilton (2018) polynomial model with VSOP87
heliocentric distances and phase angle via law of cosines. All 7
planets (Mercury-Neptune, excluding Earth). Saturn ring tilt not
modeled.

151 → 162 SQL objects. 26 → 27 test suites, all passing.
2026-02-26 12:42:01 -07:00