JPL Ephemeris

High-precision JPL ephemerides for solar-system bodies

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

satkit.jplephem.barycentric_pos(body, tm)

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

Args:

  • 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:

  • numpy.ndarray

    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

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, tm)

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

Args:

  • 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:

  • tuple

    (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

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, tm)

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

Args:

  • 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:

  • numpy.ndarray

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

satkit.jplephem.geocentric_state(body, tm)

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

Args:

  • 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:

  • tuple

    (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