Why features on WCS projected subplot are in the wrong place in matplotlib?

Question

I have a fits file about an astronomical object. I can plot it like this:

from astropy.io import fits
from astropy.wcs import WCS

hdul = fits.open(fitsfilen         


        

Answer 1

To plot in world coordinates, you need to specify the transform, e.g.:

ax = fig.gca()
ax.scatter([34], [3.2], transform=ax.get_transform('world'))

Generally, you can ignore those FITS header warnings, since none of the FITS header cards there are related to the WCS (afaik).