get_body

astropy.coordinates.get_body(body, time, location=None, ephemeris=None)

Get a SkyCoord for a solar system body as observed from a location on Earth in the GCRS reference system.

Parameters:

bodystr or list of tuple

The solar system body for which to calculate positions. Can also be a kernel specifier (list of 2-tuples) if the ephemeris is a JPL kernel.

timeTime

Time of observation.

locationEarthLocation, optional

Location of observer on the Earth. If not given, will be taken from time (if not present, a geocentric observer will be assumed).

ephemerisstr, optional

Ephemeris to use. If not given, use the one set with astropy.coordinates.solar_system_ephemeris.set (which is set to ‘builtin’ by default).

Returns:

skycoordSkyCoord

GCRS Coordinate for the body

Notes

The coordinate returned is the apparent position, which is the position of the body at time t minus the light travel time from the body to the observing location.

You can either give an explicit ephemeris or use a default, which is normally a built-in ephemeris that does not require ephemeris files. To change the default to be the JPL ephemeris:

>>> from astropy.coordinates import solar_system_ephemeris
>>> solar_system_ephemeris.set('jpl')  

Use of any JPL ephemeris requires the jplephem package (https://pypi.org/project/jplephem/). If needed, the ephemeris file will be downloaded (and cached).

One can check which bodies are covered by a given ephemeris using:

>>> solar_system_ephemeris.bodies
('earth', 'sun', 'moon', 'mercury', 'venus', 'earth-moon-barycenter', 'mars', 'jupiter', 'saturn', 'uranus', 'neptune')