CASA, the Common Astronomy Software Applications, is the primary data processing software for ALMA and the VLA, and is frequently used for other radio telescopes. CASA can handle data from single-dish, aperture-synthesis and Very Long Baseline Interferometry (VLBI) telescopes. Based on two recent reference papers, this talk will give a high-level overview of the basic structure and functionality of the CASA software, with special emphasis on recent development work that made CASA fully functional for processing VLBI data.



CASA is a user-friendly package for the manual processing of radio astronomical data and formally supports complex calibration and imaging pipelines for the ALMA and the VLA telescopes. This has also led CASA to be the foundation of one of the two calibration pipelines used by the Event Horizon Telescope, as well as two community-driven MeerKAT science pipelines and one for the GMRT.

The CASA infrastructure has been evolving and it is now offered in a pip-wheel based package, allowing the use of CASA in personal Python environments. Moreover, EC funding has facilitated the development of a Jupyter-CASA kernel. These developments enable users to work with CASA in the Jupyter notebook environment, and can be used for training, tutorials, as well as basic calibration pipelines.

We will also briefly discuss the future of CASA within the context of the proposed ngVLA and upgraded ALMA telescopes, summarize our prototyping efforts based on modern parallel infrastructures such as Dask, and mention ongoing efforts regarding advanced algorithms and modern visualization tools. CASA is being developed by a large international team of scientists and software engineers based at the NRAO, ESO, NAOJ, and JIVE.