Astronomy

Almanac appearance April astronomers bright stars brightest star called centre century changes chapter chief stars cluster colour constellation Corona dark diameter disc discovery dome double stars E. E. Barnard E. M. Antoniadi Earth equatorial fact Fireball Greenwich Halley's Comet heavens Herschel idea instrument Jupiter known light luminous lunar magnitude Majoris Mars Martian canals matter Mercury meridian meteors miles Moon Moon's motion naked eye naked-eye Nebula Neptune night Northern Hemisphere noticed object Observatory observer orbit Orion pass perhaps period planet PLATE Pole position question radiant point reach recognised Refractor regards remarkable Right Ascension ring round the Sun satellites Saturn seems seen side sidereal small telescope solar southern constellation spot Sun-spots Sun's surface Swift's Comet tail telescope tides tion total eclipse Uranus Ursa Variable Star vary Venus W. H. Pickering whilst