question about kstars catalogs

[Vincent Hourdin]

Hello, I'm a developer of Siril, I'm looking at options to integrate a
photometric star catalog for offline operation ; we currently use NOMAD
and APASS from the vizier web service.

I'm looking for more information about the kstars catalog binary format,
I was hoping you could give me pointers.

I've been looking at the code and binary format as shown in
nomadbinfiletester.c, I think it would not be difficult to use this to
create a simple search of stars in NOMAD, not using a database but
simply the file organized in "trixels".

I didn't find how the trixels were distributed in the sky, is there a
code you can point me to that converts RA,DEC to a trixel number?
In Siril we only need to get a list of stars within a radius or a
square around a target's coordinates, with a filter on magnitude too.


Another thing I was wondering is how to convert object names to
coordinates (coordinates to name could be useful too), I guess you have
a list in kstars, but would it easy to extract from whichever catalog
contains them?


Thanks a lot for your work and your help!

Vincent