Body ID Reference

Complete mapping of integer body identifiers used across all pg_orbit functions. Each function family uses its own ID space; the tables below document which IDs are valid for which functions.

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Planet IDs

Used by planet_heliocentric, planet_observe, and lambert_transfer / lambert_c3.

ID	Body	Valid for planet_heliocentric	Valid for planet_observe	Valid for lambert_*
0	Sun	Yes (returns origin)	No	No
1	Mercury	Yes	Yes	Yes
2	Venus	Yes	Yes	Yes
3	Earth	Yes	No	Yes
4	Mars	Yes	Yes	Yes
5	Jupiter	Yes	Yes	Yes
6	Saturn	Yes	Yes	Yes
7	Uranus	Yes	Yes	Yes
8	Neptune	Yes	Yes	Yes

Note

Body ID 0 (Sun) in planet_heliocentric returns the origin (0, 0, 0) by definition. Use sun_observe for topocentric Sun observation. Body ID 3 (Earth) cannot be used with planet_observe because observing Earth from Earth is undefined; use planet_heliocentric(3, t) to get Earth’s heliocentric position.

Conventions

The planet ID numbering follows the VSOP87 convention:

• IDs 1-8 map to the eight planets in order from the Sun
• No ID is assigned to Pluto (VSOP87 does not include it)
• The Sun is included as ID 0 for completeness in heliocentric queries

-- Quick lookup: all planet IDs with names
SELECT body_id,
       CASE body_id
         WHEN 0 THEN 'Sun'     WHEN 1 THEN 'Mercury'
         WHEN 2 THEN 'Venus'   WHEN 3 THEN 'Earth'
         WHEN 4 THEN 'Mars'    WHEN 5 THEN 'Jupiter'
         WHEN 6 THEN 'Saturn'  WHEN 7 THEN 'Uranus'
         WHEN 8 THEN 'Neptune'
       END AS name
FROM generate_series(0, 8) AS body_id;

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Galilean Moon IDs

Used by galilean_observe. Numbered in order of distance from Jupiter, following the Lieske L1.2 convention.

ID	Moon	Discoverer	Orbital Period	Semi-major Axis
0	Io	Galileo (1610)	1.769 days	421,700 km
1	Europa	Galileo (1610)	3.551 days	671,034 km
2	Ganymede	Galileo (1610)	7.155 days	1,070,412 km
3	Callisto	Galileo (1610)	16.689 days	1,882,709 km

-- All Galilean moon names and IDs
SELECT moon_id,
       CASE moon_id
         WHEN 0 THEN 'Io'       WHEN 1 THEN 'Europa'
         WHEN 2 THEN 'Ganymede' WHEN 3 THEN 'Callisto'
       END AS name
FROM generate_series(0, 3) AS moon_id;

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Saturn Moon IDs

Used by saturn_moon_observe. Numbered in order of distance from Saturn, following the TASS17 convention.

ID	Moon	Discoverer	Orbital Period	Semi-major Axis
0	Mimas	Herschel (1789)	0.942 days	185,539 km
1	Enceladus	Herschel (1789)	1.370 days	238,042 km
2	Tethys	Cassini (1684)	1.888 days	294,619 km
3	Dione	Cassini (1684)	2.737 days	377,396 km
4	Rhea	Cassini (1672)	4.518 days	527,108 km
5	Titan	Huygens (1655)	15.945 days	1,221,870 km
6	Iapetus	Cassini (1671)	79.322 days	3,560,820 km
7	Hyperion	Bond & Lassell (1848)	21.277 days	1,481,010 km

Note

The moon IDs are ordered by distance from Saturn, not by discovery date or ID 7 (Hyperion) being after ID 6 (Iapetus) despite Hyperion orbiting closer. This follows the TASS17 convention where the inner six moons (Mimas through Titan) are modeled as a coupled system, and the outer two (Iapetus, Hyperion) are treated with additional perturbation terms.

SELECT moon_id,
       CASE moon_id
         WHEN 0 THEN 'Mimas'     WHEN 1 THEN 'Enceladus'
         WHEN 2 THEN 'Tethys'    WHEN 3 THEN 'Dione'
         WHEN 4 THEN 'Rhea'      WHEN 5 THEN 'Titan'
         WHEN 6 THEN 'Iapetus'   WHEN 7 THEN 'Hyperion'
       END AS name
FROM generate_series(0, 7) AS moon_id;

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Uranus Moon IDs

Used by uranus_moon_observe. Numbered in order of distance from Uranus, following the GUST86 convention.

ID	Moon	Discoverer	Orbital Period	Semi-major Axis
0	Miranda	Kuiper (1948)	1.413 days	129,390 km
1	Ariel	Lassell (1851)	2.520 days	190,900 km
2	Umbriel	Lassell (1851)	4.144 days	266,000 km
3	Titania	Herschel (1787)	8.706 days	435,910 km
4	Oberon	Herschel (1787)	13.463 days	583,520 km

SELECT moon_id,
       CASE moon_id
         WHEN 0 THEN 'Miranda' WHEN 1 THEN 'Ariel'
         WHEN 2 THEN 'Umbriel' WHEN 3 THEN 'Titania'
         WHEN 4 THEN 'Oberon'
       END AS name
FROM generate_series(0, 4) AS moon_id;

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Mars Moon IDs

Used by mars_moon_observe. Numbered in order of distance from Mars, following the MarsSat convention.

ID	Moon	Discoverer	Orbital Period	Semi-major Axis
0	Phobos	Hall (1877)	0.319 days (7h 39m)	9,376 km
1	Deimos	Hall (1877)	1.263 days	23,463 km

Note

Phobos orbits closer to its parent planet than any other known moon in the solar system, completing more than three orbits per Martian day. Its orbital period (7h 39m) is shorter than Mars’s rotation period (24h 37m), so it rises in the west and sets in the east as seen from the Martian surface.

SELECT moon_id,
       CASE moon_id
         WHEN 0 THEN 'Phobos'
         WHEN 1 THEN 'Deimos'
       END AS name
FROM generate_series(0, 1) AS moon_id;

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Summary Table

Total: 8 planets + 19 moons = 27 solar system bodies computable from SQL.

Function	ID Range	Count	Theory
planet_heliocentric	0-8	9	VSOP87
planet_observe	1-2, 4-8	7	VSOP87
galilean_observe	0-3	4	Lieske L1.2
saturn_moon_observe	0-7	8	TASS17
uranus_moon_observe	0-4	5	GUST86
mars_moon_observe	0-1	2	MarsSat
lambert_transfer / lambert_c3	1-8	8	VSOP87 + Lambert