... PyFITS is a Python module developed for FITS file I/O. We demonstrated its use for FITS images and tables, illustrating the PyFITS classes and methods, as well as the array manipulation capabilities of numarray. ... PyFITS can also make use of memory mapping, which significantly enhances its performance on large FITS files, both images and tables. ... If the native byte order differs from that of a FITS file (big-endian), byte swapping is done on-the-fly within numarray when accessing data. ...