PyEphem provides an ephem Python package for performing high-precision
astronomy computations. The underlying numeric routines are coded in C
and are the same ones that drive the popular XEphem astronomy application,
whose author, Elwood Charles Downey, generously gave permission for their
use in PyEphem. The name ephem is short for the word ephemeris, which is
the traditional term for a table giving the position of a planet, asteroid,
or comet for a series of dates.

See also: https://rhodesmill.org/pyephem/