Welcome to the repository for the jplephem Python library!

The package is a Python implementation of the math that standard JPL ephemerides use to predict raw (x,y,z) planetary positions. If you are simply interested in using it, please head over to its documentation and download link on the Python Package Index:

https://pypi.python.org/pypi/jplephem

The five data packages that are available for use with it are:

https://pypi.python.org/pypi/de405

https://pypi.python.org/pypi/de406

https://pypi.python.org/pypi/de421

https://pypi.python.org/pypi/de422

https://pypi.python.org/pypi/de423

This repository is where the development version of jplephem is maintained. You will find its source code beneath the jplephem directory, alongside its setup.py file.

This repository also contains the tools for packaging JPL ephemerides so they are easy to install and import as Python packages. For example, to build your own copies of the ephemerides that are listed down at the bottom of the jplephem documentation page, you could run the following commands (skip the first two of these commands if you have already cloned this repository and are sitting in its directory):

git clone https://github.com/brandon-rhodes/python-jplephem.git
cd jplephem
bin/fetch.sh
bin/build.py

The result should be fully-compiled ephemerides ready to be installed!

If, instead of building the standard set of publicly supported ephemerides, you are interested in trying some of the more obscure offerings from the JPL, then select one of the directory names listed at the following URL:

ftp://ssd.jpl.nasa.gov/pub/eph/planets/ascii/

Some of the JPL ephemeris directories include a README file with more details, and the properties of the main ephemerides are documented in the top-level README at:

ftp://ssd.jpl.nasa.gov/pub/eph/planets/README.txt

Once you have selected an ephemeris and know its JPL directory name, go edit your copy of bin/fetch.sh and replace the standard ephemeris directory names with the alternative ephemeris that you would like to try out, and then re-run both bin/fetch.sh and bin/build.py as shown above. The result should be a new directory complete with:

• A setup.py file.
• An __init__.py file one directory lower.
• Several .npy files with actual ephemeris data.

You can then install the ephemeris locally with:

python setup.py install

Or, you can ask for it to be packaged as a .tar.gz file with:

python setup.py sdist

Either way, your new ephemeris should work like the existing ephemerides that are already listed on the Python Package Index for use with jplephem — enjoy!