docs: def get_observation_coordinates(self, x, y, hdulist_index):
          """
          Retrieves the location of a point using the coordinate system of
          the original observation, i.e. the original image before any
          cutouts were done.
  
          Returns:
            (x, y) in the original image coordinate system.
            @param x: x-pixel location in the cutout frame of reference
            @param y: y-pixel location in the cutout frame of reference
            @param idx: index of hdu in hdulist that the given x/y corresponds to.
          """
          return self.hdulist[hdulist_index].converter.get_inverse_converter().convert((x, y))