This is a Python wrapper for ERFA, Essential Routines for Fundamental Astronomy, a library derived and 'freed' from SOFA, Standards of Fundamental Astronomy.

ERFA : https://github.com/liberfa/erfa

SOFA : http://www.iausofa.org

to use this wrapper, you need:

• Python 2.7 - 3.6

• C compiler to build the module.

  . newer version of gcc (4.7+) is prefered.

download tarball

latest version is available from pypi:

https://pypi.python.org/pypi/erfa_python

or from github:

https://github.com/nirinA/erfa_python/releases

clone from github

you can clone the project repository at:

https://github.com/nirinA/erfa_python/

• to build the module, unpack the tarball, cd to erfa_python directory and do the usual:

    python setup.py build

note for OS X:

• on OSX platform, it seems that erfa needs to be build as a library, and some 'compatibility version' needs to be adjusted thanks to @vhaasteren for reporting and solving this issue, see:

#4

• if previous version of erfa_python is already installed in site-packages, be sure to remove all related files before installing the new version.

• install (may need root privilege) with:

    python setup.py install

a test-suite adapted from t_erfa_c.c is provided. do:

    python erfa_test.py

to validate erfa_python module.

note:

some test fail with older version of gcc (4.5). thanks to @yanwang2012 for this report, see:

#6

on-line documentation is available with:

    pydoc erfa

to generate a html version:

    pydoc -w erfa

and, from the interpreter:

   >>> help(erfa)
   >>> help(erfa.<function>)

to be updated

more detailed C-api reference of liberfa is available in doc/api.rst. a html version can be built:

    cd doc   
    mkdir _build  
    sphinx-build . _build

you need sphinx and its dependencies to build the doc.

some examples adapted from SOFA documentation can be found in examples/ directory.

. ex_ast.py

example of Astrometry Tools

. ex_pn.py

example of tools for Earth Attitude

. ex_ts.py

example of Time Scale and Calendar Tools

. ex_ephem.py

basic example of Ephemerids for Sun and Major planets

. 2010201

• update from SOFA release 14.

. 20170421

• update from SOFA release 13.
• this release replaces the IAU 1976 value of astronomical unit with the IAU 2012 value.
• codes are all backward compatible but results are not, especially those using erfa.ASTROM
• erfa_test.py has been updated accordingly

. 2016123

• update from SOFA release 12, revised on 2016-12-23.
• tests for fk52h and starpm are relaxed, as they failed with Python3.6 built with all optimization enabled.

. 20160503

• add new routines from SOFA release 12.

. 20150211

• add new functions icrs2g and g2icrs from latest SOFA release

. 20141016

• upload a windows binary to PyPi.

. 20140921

• update erfa.c from latest sofa release.

. 20140601

• erfa source is included, so a pre-installed liberfa is no longer required.

. 20140530

• update ex_ast.py
• fix _erfamodule.c docstring

. 20140127

• support for Python-3.4.

. 20131226

• completed routines from the latest SOFA release.
• renamed and slightly reworked the C extension to _erfamodule.c

. 20131222

• added a few routines from the latest SOFA release.

. 20130830

• registered to PyPi

. 20130815

• rewrote the wrapper from SOFA to ERFA