4.6.1 On the CASA side

The proper exportation is done by invoking the casagildas() tool. ⁴. casagildas() scans the Measurement Set using the listobs() tool, then uses a Python script that parses the output of listobs() to prepare a Python script named casa_uvfits.py.

It is then up to the user to execute this Python script, using the casagildas("Do") command that creates one UVFITS file per Source and Spectral window in the input Measurement Set. Thus, the sequence

  vis='MyMeasurementSet.ms'   # Setup the input Measurement Set filename
  casagildas("List")          # List its content and create the export script
  casagildas("Do")            # Execute the export script

will create a set of

  Source-Frequency.uvfits

files, where Source is the source name and Frequency is the central frequency of the spectral window in MHz, for all combinations of sources and spectral windows.

Important note: Because, contrary to e.g. tclean, CASA task exportuvfits only accept one Measurement Set at a time, if you have several observing blocks with the same spectral setup, you should concatenate all relevant measurement sets into a single one, and use the casagildas() tool on it.

Caution: The recipe above does not work?

• First, be sure to use a recent enough Casa version (Python 3 based),
• Second, the vis argument only accepts one Measurement set, not a list. Use concat before if needed.
• If none of the above works, this is probably because of an obsolete version. Remove $HOME/.casa/casa2gildas.py, then launch IMAGER once, and then CASA again. This will re-install an up-to-date version of the casagildas() tool.
• the exportuvfits task of CASA has bugs when used on some measurement sets, and may deliver incomplete UVFITS files. See section A for details and possible work-arounds.
• if all of that still fails, contact IMAGER support.