=== Dealing with large FITS files===
When taking very large data cubes, the file sizes may grow unmanageably large. On older 32-bit systems, FITS files were automatically truncated at 2GB and rolled over, but on the new 64-bit systems we use, this does not happen. Consequently, very large FITS files may be generated. To cope with these, there is a utility called split_fits.py. This script prompts for the name of a FITS file to split, and the number of chunks into which it should be split. It then splits the large file into this number of smaller files. The FITS header is identical in each of the resulting files.
The script split_fits.py is installed on both astro.cape and astro.suth, in the directory /usr/local/saao/bin. To run it, type split_fits.py, then when prompted enter the filename and number of chunks to produce. The output files are put in the same directory as the input file.