Ephemeris queries¶
Use GetEphemerisAsStateVectors to get state vectors of any SPICE-known body observed from any other. The server already has the standard generic kernels loaded; you don't manage them.
Earth as seen from the Sun¶
{
"observerName": "SUN",
"targetName": "EARTH",
"frame": "ICRF",
"startTime": "2024-06-21T12:00:00",
"endTime": "2024-06-21T12:00:00",
"timeStep": 86400,
"aberrationCorrection": "None"
}
Returns one state vector — position (m) and velocity (m/s) of Earth in ICRF, with the Sun as observer.
The Moon over a day, hourly samples¶
{
"observerName": "EARTH",
"targetName": "MOON",
"frame": "ICRF",
"startTime": "2024-06-21T00:00:00",
"endTime": "2024-06-22T00:00:00",
"timeStep": 3600,
"aberrationCorrection": "LT+S"
}
24 state vectors come back. Aberration LT+S applies one-way light time and stellar aberration — appropriate for what a telescope would actually see.
What about properties?¶
For intrinsic body properties (radii, GM, J2, frame name), use GetCelestialBodyProperties instead.
Choosing a frame¶
ICRF is the safe default for inertial work. For body-fixed Earth coordinates you usually want ITRF93 (high-precision Earth orientation) or the body's IAU_* frame for first-order needs. See Standards & Units → Reference frames.
Aberration¶
If you are asking "where is this body physically right now" — None.
If you are asking "where will I see it from here" (telescope, antenna pointing) — LT+S.
Other variants (CN, CN+S, XLT, XLT+S) match SPICE's aberration codes and are documented in the IO.Astrodynamics docs.