Updating CASA's ephemeris tables for solar system objects

CASA provides ephemeris data for the Solar System objects used in the setjy task so this is generally not need to do for a general user. But in a case that the tables need to be regenerated or updated the following is a short description of the procedure.

Obtaining the ephemeris data

Access JPL-Horizons System and obtain the data by query. The tools in request.py in recipes/ephemerides are used to request the data.

request_from_JPL() - request ephemerides via email for a object for a given date range. Or alternatively (particularly for an SS object not supported in setjy such as a comet), you can get it via JPL-Horizons Web interface (saved as a plain text) but be sure to request the quantities =1,14,15,17,19,20,24.

Convert the data in the ascii file to a CASA table

Then convert it to a CASA table via JPLephem_reader.readJPLephem() The script that perform these steps: make-casaephem-from-JPL-Horizons.py

T.Tsutsumi 2014-10-07