Spot the difference!

© Ilse van Bemmel

The CASA software is now capable of calibrating the majority of VLBI observations. A paper describing the new functionality and a comparison with the AIPS package is now published in PASP. The calibration quality of CASA and AIPS is comparable down to a level of a few degrees in phase and a few percent in amplitude. As demonstrated above, this results in nearly identical images with AIPS on the left and CASA on the right. Any remaining differences are largely due to different choices in software architecture and implementation.

The CASA VLBI paper is published jointly with the new CASA Reference paper, which describes the CASA 6 series at a higher level. Everyone who uses CASA for their data processing is encouraged to refer to these papers, where appropriate.

The work on VLBI processing in CASA is not finished. Functionality to improve the Earth Orientation Parameters, handling of phase-cal tones and polarization calibration with resolved calibrators are some of the items still on the wish list. With the upcoming changes to the CASA architecture the processing will also become much more efficient, so stay tuned!