Now in a superbly redesigned, two-color landmark 20th edition, this combination start atlas and reference work has no match in the field, First published in 1910, Norton's owes much of its legendary success to its unique maps, arranged in slices known as gores, each covering approximately one-fifth of the sky. Every start visible to the naked eye under the clearest skies- down to magnitude 6.5-is charted, along with star clusters, nebulae, and galaxies. Extensive tables of data on interesting objects for observation accompany each of the precision-drawn maps. Preceding the maps is the unique and authoritative reference handbook covering timekeeping and positional measurements on the celestial sphere; the sun, moon, and other bodies of the solar system; telescopes and other equipment for observing and imaging the sky; and stars, nebulae, and galaxies. Throughout, succinct fundamental principles and practical tips guide the reader into the night sky. The appendices Units and Notation, Astronomical Constants, Symbols and Abbreviations, and Useful Addresses complete what has long been the only essential reference for the stargazer.