Takes an input data file with (x,y) coordinates and assigns (alpha, delta) astrometry, given a *_corr.fits file previously obtained from the astrometry.net service.

The algorithm used to transform (x,y)-->(ra,dec) is the one developed by Jarno Elonen, based on the article Fitting affine and orthogonal transformations between two sets of points, H. Späth (2004).

It can also work with a list of stars manually cross-matched and stored in a *_corr.fits file with column names:

field_ra, field_dec, field_x, field_y

It can also generate the file needed to feed the astrometry.net service.

The astrometry.net takes its coordinated from the USNO-B catalog which:

...is believed to provide all-sky coverage, completeness down to V = 21, 0.2 arcsecond astrometric accuracy at J2000

Python 3, astropy, numpy scipy, matplotlib