def _apparent_position_in_true_coordinates(skycoord):
 (jd1, jd2) = get_jd12(skycoord.obstime, u'tt')
 (_, _, _, _, _, _, _, rbpn) = erfa.pn00a(jd1, jd2)
 return SkyCoord(skycoord.frame.realize_frame(skycoord.cartesian.transform(rbpn)))

def _apparent_position_in_true_coordinates ( skycoord ) : ( jd1 , jd2 ) = get_jd12 ( skycoord . obstime , u'tt' ) ( _ , _ , _ , _ , _ , _ , _ , rbpn ) = erfa . pn00a ( jd1 , jd2 ) return SkyCoord ( skycoord . frame . realize_frame ( skycoord . cartesian . transform ( rbpn ) ) )
convert skycoord in gcrs frame into one in which ra and dec are defined w .