Popular Astronomy, Volume 52

absorption appear Arabic Astronomical Society August average B.Taur binary bright catalogue Cepheids clusters color computed crater cycle Cygni dark nebulae derived diameter distance double stars earth eclipse Ephemeris faint stars fall field fireball galactic center galactic plane galaxy given Greenwich Harvard indicated interstellar investigation iron July Jupiter kamacite km/sec latitude Lick Observatory light curve lines magnitude Mars mass maximum measured meteor meteorite method miles Milky months moon navigation Nova object observations Observatory obtained OCCULTATIONS VISIBLE October orbits Otto Struve oxide parallaxes perihelion PERIODIC COMET photographic planet plates position present probably problem proper motions Pulkovo radial velocities region relative right ascension rotation Saturn Shapley solar spectral class spectral types spectrum spots star density Struve sunspots surface Table telescope temperature tion University Variable Star VISIBLE IN LONGITUDE visual Wilson Yerkes