eph 0.2.0

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Readme
======

The ``eph`` package provides some useful functions, classes and tools
to`retrieve`, `parse` and `manipulate` ephemerides.

Basic Usage
-----------

.. code-block:: python

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

print(ephemeris) # print data

or, the one-liner

.. code-block:: python

import eph

print(eph.JplReq().read('.ephrc', 'jplparams').set({'COMMAND': '399', 'START_TIME': '2007-11-17', 'STOP_TIME': '2017-04-22'}).query().parse())


The content of :file:`.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)

.. code-block:: ini

[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 to retrive ephemerides from services like JPL Horizons.
To use it, open the terminal and type

.. code-block:: bash

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

and you get 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 with

.. code-block:: bash

$ eph --help