I recently spent a few weeks at the Medicina Radiotelescope, Italy, working on getting data from a correlator into a format that CASA and AIPS could read. To do this, I made a python script to convert the data into a FITS IDI file.
The FITS Interferometry Data Interchange Convention (“FITS-IDI”) is a set of conventions layered upon the standard FITS format to assist in the interchange of data recorded by interferometric telescopes, particularly at radio frequencies and very long baselines.
pyFitsidi is a collection of functions that create headers and data units that conform to the FITS-IDI convention. It was written primarily to convert data from a CASPER correlator into a format that can be imported into data reduction packages such as AIPS++ and CASA.
pyFitsidi is built upon pyFITS and numpy. Astronomical coordinate calculations are done with pyEphem, and the HDF file reading is done with pyTables (although you could use h5py also). HTML documentation (generated with sphinx), can be found in docs/_build/html, and there is also a PDF file.
pyFitsidi @ Github
Much more info on the FITS IDI convention can be found on its official page
pyFitsidi uses pyFITS for file I/O, so its worth getting familiar with pyfits
Finally, there are useful FITS resources at the NASA FITS website