code: def get_pixbeam(self, ra, dec):
          
          # If there is no psf image then just use the fits header (plus lat scaling) from the wcshelper
          if self.data is None:
              return self.wcshelper.get_pixbeam(ra, dec)
          # get the beam from the psf image data
          psf = self.get_psf_pix(ra, dec)
          if not np.all(np.isfinite(psf)):
              log.warn("PSF requested, returned Null")
              return None
          return Beam(psf[0], psf[1], psf[2])
docs: Get the psf at the location specified in pixel coordinates.
          The psf is also in pixel coordinates.
  
          Parameters
          ----------
          ra, dec : float
              The sky position (degrees).
  
          Returns
          -------
          a, b, pa : float
              The psf semi-major axis (pixels), semi-minor axis (pixels), and rotation angle (degrees).
              If a psf is defined then it is the psf that is returned, otherwise the image
              restoring beam is returned.