docs: def parse_coordinates(self, coords_str):
          """
          Returns a pair of PyEphem-compatible coordinate strings (Ra, Dec).
  
          If the star has no coordinates in GCVS (there are such cases), a pair
          of None values is returned.
          """
          if coords_str.strip() == '':
              return (None, None)
          ra = '%s:%s:%s' % (coords_str[0:2], coords_str[2:4], coords_str[4:8])
          dec = '%s:%s:%s' % (coords_str[8:11], coords_str[11:13], coords_str[13:15])
          return (ra, dec)