JPL Ephemeris

High-precision JPL ephemerides for solar-system bodies

For details, see: https://ssd.jpl.nasa.gov/

satkit.jplephem.barycentric_pos(body: satkit.solarsystem, tm: satkit.time | list[satkit.time] | numpy.typing.ArrayLike) → numpy.typing.NDArray[numpy.float64]

Return the position of the given body in the Barycentric coordinate system (origin is solarsystem barycenter)

Parameters:

  • body (satkit.solarsystem) – Solar system body for which to return position

  • tm (satkit.time|numpy.ndarray|list) – Time[s] at which to return position

Returns:

3-vector of Cartesian position in meters, with the origin at the solar system barycenter. If input is list or numpy array of N times, then r will be Nx3 array

Return type:

numpy.ndarray

Notes

  • Positions for all bodies are natively relative to solar system barycenter, with exception of moon, which is computed in Geocentric system

  • EMB (2) is the Earth-Moon barycenter

  • The sun position is relative to the solar system barycenter (it will be close to origin)

satkit.jplephem.barycentric_state(body: satkit.solarsystem, tm: satkit.time | list[satkit.time] | numpy.typing.ArrayLike) → Tuple[numpy.typing.NDArray[numpy.float64], numpy.typing.NDArray[numpy.float64]]

Return the position & velocity the given body in the barycentric coordinate system (origin is solar system barycenter)

Parameters:

  • body (satkit.solarsystem) – Solar system body for which to return position

  • tm (satkit.time|numpy.ndarray|list) – Time[s] at which to return position

Returns:

(r, v) where r is the position in meters and v is the velocity in meters / second, with the origin at the solar system barycenter. If input is list or numpy array of N times, then r and v will be Nx3 arrays

Return type:

tuple

Notes

  • Positions for all bodies are natively relative to solar system barycenter, with exception of moon, which is computed in Geocentric system

  • EMB (2) is the Earth-Moon barycenter

  • The sun position is relative to the solar system barycenter (it will be close to origin)

satkit.jplephem.geocentric_pos(body: satkit.solarsystem, tm: satkit.time | list[satkit.time] | numpy.typing.ArrayLike) → numpy.typing.NDArray[numpy.float64]

Return the position of the given body in the GCRF coordinate system (origin is Earth center)

Parameters:

  • body (satkit.solarsystem) – Solar system body for which to return position

  • tm (satkit.time|numpy.ndarray|list) – Time[s] at which to return position

Returns:

3-vector of cartesian Geocentric position in meters. If input is list or numpy array of N times, then r will be Nx3 array

Return type:

numpy.ndarray

satkit.jplephem.geocentric_state(body: satkit.solarsystem, tm: satkit.time | list[satkit.time] | numpy.typing.ArrayLike) → Tuple[numpy.typing.NDArray[numpy.float64], numpy.typing.NDArray[numpy.float64]]

Return the position and velocity of the given body in Geocentric coordinate system (GCRF)

Parameters:

  • body (satkit.solarsystem) – Solar system body for which to return position

  • tm (satkit.time|numpy.ndarray|list) – Time[s] at which to return position

Returns:

(r, v) where r is the position in meters and v is the velocity in meters / second. If input is list or numpy array of N times, then r and v will be Nx3 arrays

Return type:

tuple