[AstroPy] API question: Instantiating of time/coord and similar

Tim Jenness tim.jenness at gmail.com
Thu May 3 00:41:28 EDT 2012

On Wed, May 2, 2012 at 9:28 PM, James Turner <jturner at gemini.edu> wrote:
>> No-one has ever asked us about AST's license. It was a triumph to
>> allow it to be shipped with GPL when it first came out (and that was
>> mainly driven by Mark Calabretta's wcslib being GPL). We can
>> definitely try to work out how to get it changed to a looser license
>> (the main issue being to find out which person you have to talk to and
>> whether they even care) but I assume wcslib would have to change with
>> it.
> Thanks for the info. If it were available under a BSD licence or
> similar, that would make things easy :-). I had assumed the GPL
> copyleft was a deliberate restriction because, for example, SLALIB
> was available at one time under terms that effectively seemed to be
> tightened by JAC moving Starlink to GPL (sorry if that's not quite
> an accurate statement but it's how I ended up using the version
> distributed with IRAF instead of the latest one).

At the risk of going off topic... The Starlink software used to be
distributed using the Starlink software licence which was a
restrictive non-commercial use licence that caused lots of trouble. It
was a major effort to convince everyone that we could switch over to
GPL. It's funny how this left a feeling that the software became more
restrictive as we were trying for the complete opposite. AST has
always been GPL because of WCSLIB and because Starlink were really
trying for broad adoption back in 1997.

SLA is a special case since the Fortran was Starlink licence and the C
was a private Pat Wallace licence. I recently wrote an API-compatible
version of SLA (called PAL) in C (using GPL) as a layer on top of SOFA
(which recently got into debian with a licence tweak from the most
recent SOFA release).

> I actually quite like the GPL -- it just becomes a pain when some
> project that matters to you decides not to use it for one reason or
> another.

I have no objection to change. It's all in the bureaucracy...

> I believe WCSLIB was changed quite recently (maybe a couple of years
> ago) to LGPL, so I think that should be a non-issue now.

AST doesn't link against WCSLIB. It locally modifies it and embeds it
deep in the library.

Tim Jenness

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