code: def healpix_to_skycoord(self, healpix_index, dx=None, dy=None):
          
          if self.frame is None:
              raise NoFrameError("healpix_to_skycoord")
          lon, lat = self.healpix_to_lonlat(healpix_index, dx=dx, dy=dy)
          representation = UnitSphericalRepresentation(lon, lat, copy=False)
          return SkyCoord(self.frame.realize_frame(representation))
docs: Convert HEALPix indices (optionally with offsets) to celestial coordinates.
  
          Note that this method requires that a celestial frame was specified when
          initializing HEALPix. If you don't know or need the celestial frame, you
          can instead use :meth:`~astropy_healpix.HEALPix.healpix_to_lonlat`.
  
          Parameters
          ----------
          healpix_index : `~numpy.ndarray`
              1-D array of HEALPix indices
          dx, dy : `~numpy.ndarray`, optional
              1-D arrays of offsets inside the HEALPix pixel, which must be in
              the range [0:1] (0.5 is the center of the HEALPix pixels). If not
              specified, the position at the center of the pixel is used.
  
          Returns
          -------
          coord : :class:`~astropy.coordinates.SkyCoord`
              The resulting celestial coordinates