Popular Astronomy, Volume 52

absorption appear April Arabic Astr Astronomical Society August average B.Taur binary bright Catalogue Cepheids clusters color computed coördinate number crater cycle Cygni derived diameter distance distribution double stars earth eclipse emission Ephemeris fall field fireball galactic center galaxy given Greenwich Harvard indicated interstellar investigation July Jupiter km/sec latitude Lick Observatory light curve lines magnitude Mars mass maximum measured meteor meteorite method miles Milky months Moon nebulae Notes Nova object Observatory obtained OCCULTATIONS VISIBLE October orbit Otto Struve oxide parallaxes perihelion photographic planet plates position present probably proper motions Pulkovo radial velocities record region relative right ascension rotation Saturn Shapley siderite solar spectral class spectral types spectroscopic spectrum spots SS Cygni star density stellar Struve sunspots Table telescope temperature tion University Variable Star VISIBLE IN LONGITUDE visual Wilson