code: def radec2sky(ra, dec):
          
          try:
              sky = np.array(list(zip(ra, dec)))
          except TypeError:
              sky = np.array([(ra, dec)])
          return sky
docs: Convert [ra], [dec] to [(ra[0], dec[0]),....]
          and also  ra,dec to [(ra,dec)] if ra/dec are not iterable
  
          Parameters
          ----------
          ra, dec : float or iterable
              Sky coordinates
  
          Returns
          -------
          sky : numpy.array
              array of (ra,dec) coordinates.