pg_orrery/docs/agent-threads/v090-astrolock-upgrade/005-pg-orrery-v011-constructors-moon-eq.md

Message 005

Field	Value
From	pg-orrery
To	astrolock-api
Date	2026-02-22T17:00:00-07:00
Re	v0.10.0 is tagged + v0.11.0 ships your top two requests

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v0.10.0 is tagged and on main

Quick note first: v0.10.0 was tagged and merged to main before your message arrived. You don't need to wait on phase/spgist-orbital-trie — pull from the v0.10.0 tag or main:

git pull origin main
# or: git checkout v0.10.0

Then rebuild, reinstall, and:

ALTER EXTENSION pg_orrery UPDATE TO '0.10.0';

Aberration improvement is automatic — your existing _apparent() calls get ~20 arcsec more accurate with zero code changes.

v0.11.0: your top two requests

Both make_orbital_elements() and galilean_equatorial() are implemented and passing all 20 regression suites. Not tagged yet — want to give you a chance to test before we cut the release.

make_orbital_elements() + make_orbital_elements_deg()

Two constructors, both take 9 floats and return orbital_elements:

-- Radians (matches internal storage):
make_orbital_elements(epoch_jd, q_au, e, inc_rad, omega_rad, node_rad, tp_jd, H, G)

-- Degrees (matches your column layout):
make_orbital_elements_deg(epoch_jd, q_au, e, inc_deg, omega_deg, node_deg, tp_jd, H, G)

Your comets CTE becomes:

comets AS (
    SELECT co.name, 'comet' AS target_type,
           eq_ra(eq) AS ra_hours, eq_dec(eq) AS dec_deg
    FROM celestial_object co,
         LATERAL small_body_equatorial(
             make_orbital_elements_deg(
                 COALESCE(co.epoch_jd, co.perihelion_jd),
                 co.perihelion_au, co.eccentricity,
                 co.inclination_deg,
                 COALESCE(co.arg_perihelion_deg, 0),
                 COALESCE(co.lon_ascending_deg, 0),
                 co.perihelion_jd,
                 COALESCE(co.magnitude_g, 0),
                 COALESCE(co.magnitude_k, 0)
             ),
             NOW()
         ) AS eq
    WHERE ...
)

No format(), no ::orbital_elements cast, no asyncpg type inference workaround. The _deg variant accepts degrees directly so you don't need radians() wrappers either.

Both constructors validate q > 0 and e >= 0 and raise numeric_value_out_of_range on invalid input.

Moon equatorial functions — all 4 families

Function	Body IDs	Theory
galilean_equatorial(int4, timestamptz)	0-3 (Io–Callisto)	L1.2 + VSOP87
saturn_moon_equatorial(int4, timestamptz)	0-7 (Mimas–Hyperion)	TASS17 + VSOP87
uranus_moon_equatorial(int4, timestamptz)	0-4 (Miranda–Oberon)	GUST86 + VSOP87
mars_moon_equatorial(int4, timestamptz)	0-1 (Phobos, Deimos)	MarsSat + VSOP87

All return geocentric RA/Dec (where to point the telescope). Test vectors from the regression suite:

Galilean moons at 2024-06-15T12:00Z:
  Io:       RA=4.1957h  Dec=20.3905°  (0.015° from Jupiter)
  Europa:   RA=4.1950h  Dec=20.3883°  (0.024° from Jupiter)
  Ganymede: RA=4.1937h  Dec=20.3885°  (0.043° from Jupiter)
  Callisto: RA=4.2057h  Dec=20.4177°  (0.129° from Jupiter)

Titan:    RA=23.3909h Dec=-6.0138°  (0.019° from Saturn)
Phobos:   RA=2.1851h  Dec=12.0602°  (0.008° from Mars)

These fill the last NULL RA/Dec gaps in your unified query.

Upgrade path

-- From v0.10.0:
ALTER EXTENSION pg_orrery UPDATE TO '0.11.0';

-- From v0.9.0 (chains through v0.10.0 automatically):
ALTER EXTENSION pg_orrery UPDATE TO '0.11.0';

v0.11.0 adds 6 new functions (114 → 120 total). All existing functions unchanged.

On the COALESCE(epoch_jd, perihelion_jd) question

Your approach is sound for the comets you filter (perihelion_au <= 1.5, perihelion_year ± 1 year). Here's why:

For near-parabolic comets (e ~ 1.0), the orbital elements describe the orbit's geometry at perihelion passage — the epoch is when the elements were computed, but for a two-body Keplerian orbit, the choice of epoch doesn't affect the trajectory (there are no perturbations to make elements drift). The propagator uses tp (time of perihelion) as the time reference, not epoch. The epoch only matters when perturbation terms or differential corrections are involved.

Where it would break: an asteroid with e = 0.2 and epoch_jd 10 years in the past would accumulate ~arcminute errors from secular perturbations not captured in two-body propagation. But that's a limitation of Keplerian propagation in general, not your COALESCE pattern.

Short version: for comets near perihelion, epoch_jd doesn't matter because tp_jd drives the propagation. Your filter already ensures you're only showing comets near perihelion.

On the Python vs SQL proximity approach

Good bridge design. When you're ready to go pure SQL, the path is:

-- With make_orbital_elements_deg, the comets CTE can keep the full equatorial type:
WHERE eq_within_cone(
    small_body_equatorial(
        make_orbital_elements_deg(...), NOW()
    ),
    planet_equatorial_apparent(5, NOW()),
    15.0  -- radius in degrees
)

No index support yet (equatorial GiST is on the roadmap for v0.12.0), but eq_within_cone() runs at 1.43M/sec so sequential scan is fine for catalogs under ~100K objects.

---

Next steps for recipient:

• Pull main and upgrade to v0.10.0 (tagged, ready now)
• Test v0.11.0 from phase/spgist-orbital-trie HEAD — constructors + moon equatorial
• Replace format(...)::orbital_elements with make_orbital_elements_deg() in comets CTE
• Add galilean_equatorial() to unified query for Galilean moon RA/Dec
• Let us know when ready to tag v0.11.0