Convert the PSF/Star ellipticity to sky coordinates

[aguinot]

Having the PSF/Star ellipticity measured using the sky coordinates would make the validation easier.
This is straightforward to implement with recent Galsim update:

galsim.hsm.FindAdaptiveMom([...], use_sky_coords=True)

It will also required to provide the WCS to the galsim Image which are available through the SETools catalogue:

header_data = setools_cat[1].data
header = fits.Header.fromstring('\n'.join(header_data[0][0]), sep='\n')
wcs = galsim.AstropyWCS(header=header)

local_wcs = wcs.jacobian(image_pos=galsim.PositionD(obj["X"], obj["Y"]))