I'm working on a game engine of sorts, and one thing I did for a previous game which was under the GPL was I had a night sky with the constellations visibly connected and I'd like to do that again. I don't know where my data set originally came from but I do have a note that it was GPL, so it likely came from Stellarium, which is GPL licensed. For this I need the dataset to come from the public domain, us government, permissively licensed, etc.
If possible I'm after the coordinates in the sky, brightness, maybe class and name, but also some mechanism to know which stars would be connected in classic constellations.
I've found some data sets which contain the star data I'm after, though they would take some effort to parse and pull out the data I'm after, but I can't seem to find anywhere online, except stellarium, which provides star constellation connectivity. Any ideas?
I've gotten this list so far from what I can tell:
- Stellarium: Has everything. GPL (Really restrictive) But has things like a constellationship file, i.e. https://github.com/Stellarium/stellarium/blob/master/skycultures/western/constellationship.fab
- HYG: Great database, has everything I want, but licensed under restrictive CC 2.5 SA https://github.com/astronexus/HYG-Database No Constellations
- BSC5: No explicit license, but created from NASA/ADC, data should be public domain. Good data set, difficult to parse, no star connectivity. (Best candidate for raw star database)
- UCAC5: Navy (public domain), data set not geared for visible light.
- HIP (used by Stellarium for stars) - Difficult to parse through, ESA (correct license) http://cdsarc.u-strasbg.fr/ftp/cats/I/239/hip_main.dat.gz
Are there any standards of what stars make up the primary connections in constellations? Or does it just happen to be whoever puts it together?
P.S. If I ever do succeed, I will release the database (probably 3-4k stars is all I will need with connectivity) under the MIT license to permit inclusion in any commercial or noncommercial projects.