py311-spktype21

Supporting module for jplephem to handle data type 21

This module computes positions and velocities of a celestial small body, from a NASA SPICE SPK ephemeris kernel file of data type 21 (Extended Modified Difference Arrays). See http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/FORTRAN/req/spk.html You can get SPK files for many solar system small bodies from HORIZONS system of NASA/JPL. See https://ssd.jpl.nasa.gov/?horizons This module reads SPK files of data type 21, one of the types of binary SPK file. At the point of Oct. 2018, HORIZONS system provides files of type 21 as binary SPK files by default. You can get type 21 binary SPK file for celestial small bodies through TELNET interface by answering back 'B' for 'SPK file format'. Also you can get type 21 binary SPK file from: https://ssd.jpl.nasa.gov/x/spk.html