Astronomy

Algol Alpha ancient Andromeda appear asteroids astronomers atmosphere axis beautiful believed Betelgeuse Bradley FIG bright stars brighter brightest star brilliance celestial equator celestial sphere circle clouds color comet composed constellation craters Cygnus dark diffuse nebulae disc discovered distance double star Earth equinox faint full moon galactic Galileo globular clusters gravitational group of stars heavenly bodies horizon instrument interesting Jupiter known latitude Levett Bradley light light-years magnitude Mars mass measured Mercury meteorite meteors Milky Way Galaxy million Moon's orbit motion Mount Wilson Observatory moving naked eye nearly nebular theory night North Pole Northern object observer open clusters Orion passing path period phase photographs planetary nebulae planetesimals planets Pleiades position probably reflecting telescope reflector refracting revolve rotation satellites Saturn seen shines side solar system spectra spectroscope spectrum spiral Sun's Sunspots surface tail temperature tion total eclipse variable stars Venus visible Yerkes Observatory zodiac