code: def sky2pix(self, pos):
          
          pixel = self.wcs.wcs_world2pix([pos], 1)
          # wcs and pyfits have oposite ideas of x/y
          return [pixel[0][1], pixel[0][0]]
docs: Convert sky coordinates into pixel coordinates.
  
          Parameters
          ----------
          pos : (float, float)
              The (ra, dec) sky coordinates (degrees)
  
          Returns
          -------
          pixel : (float, float)
              The (x,y) pixel coordinates