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Submitter: Tony Willis, Jan Noordam
Description: In November 1991, a group of people representing most of the major radio telescopes in the world met at the Parkes Radio Observatory in Australia, to plan for the joint development of a new data processing system, to be called aips++. It would integrate all the powerful new calibration and imaging algorithms that had been developed after the invention of selfcal around 1980. It would be written in such a way that the package could evolve naturally with subsequent developments.

Actual work on the new system began in 1992, so 2017 is the 25th anniversary of the birth of aips++. Of course it was found that working together across the continents was not that easy, especially since the people involved had all written their own software packages and tended to be a little individualistic. Indeed aips++ had a long and difficult gestation period before evolving into CASA.

Apart from the inevitable culture wars, and rank amateurism, the project suffered from lack of focus because it was not crucial to a single major telescope (that happened later, when CASA was aimed at ALMA). But the biggest mistake was the failure to start with the implementation of a truly superior uv-data handling system that would have attracted users even without the new algorithms. Still, it produced some highly valuable components (e.g. a widely accepted data-format, fitting, coordinate conversions), most of them written by Dutchmen. And despite all the wrangling it fomented a worldwide software community in our field.

Over the past 25 years the founding fathers have matured as much as aips++ itself has, turning them into wiser and sadder men. So here is how they look today in comparison with 1991. The mugshots are ordered in the same left to right sequence as their younger versions in the original photo. We have Mark Calabretta (CSIRO), Jan Noordam (ASTRON), Bob Sault (then BIMA), Dave Shone (then Jodrell Bank), Geoff Croes (then head of computing at NRAO), Tim Cornwell (then NRAO), Ray Norris (CSIRO) and Tony Willis (DRAO).

We have also added Brian Glendenning (NRAO), at the lower right, as an honorary founding father. Probably more than anyone else, he was responsible for actually getting aips++ off the ground in the early 1990s. As Brian has pointed out aips++/CASA is now older than the original AIPS was when development of aips++ began!

Today, CASA can be considered a success. It supports the ALMA and JVLA telescopes, and the software libraries are widely used in applications scattered around the world.
Copyright: CASA
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