Getting Started

Basic Usage

import eph

req = eph.JplReq() # create the request
req.read('.ephrc', 'jplparams') # read parameters from 'jplparams' section in '.ephrc' file
req.set({
    'COMMAND': 'earth',
    'START_TIME': '2007-11-17',
    'STOP_TIME': '2017-4-22'
    }) # set parameters from dictionary
res = req.query() # perform the request obtaining a response from Jpl Horizons service
ephemeris = res.parse() # extract and parse the ephemeris contained in the http response

ephemeris.write() # print data to stdout

The content of .ephrc can be something like this (see ftp://ssd.jpl_process.nasa.gov/pub/ssd/horizons_batch_example.long for a complete description of JPL parameters)

[jplparams]
CENTER='@0'
OBJ_DATA=NO
MAKE_EPHEM=YES
TABLE_TYPE=VECTORS
VEC_TABLE=1
REFERENCE_PLANE=ECLIPTIC
REF_SYSTEM=J2000
OUT_UNITS=AU-D
CSV_FORMAT=YES
VEC_LABEL=NO
STEP_SIZE=1d

Command line tool

eph package also provides a command line tool:

$ eph 2007-11-17 2017-4-22 venus

This command gives you an ephemeris table of Venus starting from 2007-11-17 to 2017-4-22. You can also change the reference frame, the time-step size, the output etc.. through the options provided. Check available options typing

$ eph --help