Furlongs M94 Mm 2M1207 graininess milliarcseconds Damerau kiloparsecs parsec ating Rajupalem Guhisar Gm periastron Hipparcos arcseconds AU TRGB redshift picometers PNLF Trogons cartogram lightyears parallax dQundf mufawada NGC kly angstroms Turmalina quadrance Modestino allozyme Cepheid