The universe beyond our own has been an object of scientific inquiry and a preoccupation of avid stargazers from antiquity up to the present day, and this preoccupation has evolved into a complex field in which mysteries are unlocked and discoveries are made on a constant basis. The Astronomy Encyclopedia covers the full width and breadth of the discipline and includes the latest and most important advances. In more than 3,000 alphabetically organized articles accompanied by 500 stunning color and black and white photographs, star maps, and diagrams, The Astronomy Encyclopedia covers everything both the researcher and general enthusiast wants to knowfrom adaptive optics and cold dark matter to Islamic astronomy and the principle of equivalence. It includes a host of major articles on the cornerstones of astronomical investigation, such as the Milky Way, the sun and planets, optical and radio telescopes, stars, black holes, astrophysics, observatories, astronomical photography, space programs, the constellations and famous astronomers. Also featured are tables which display relevant data such as the brightest stars in the major constellations, annual meteor showers, major variable stars, dwarf stars, and energy production processes in the sun. More than 100 astronomers from leading universities and observatories, each an expert in a specialized area of the field, wrote and reviewed the entries to ensure their authority. Patrick Moore, distinguished astronomer and longtime host of the popular BBC television program The Sky at Night, serves as the general editor for this most up-to-date and reliable reference work. A glimpse into humanity's last great frontier, the Astronomy Encyclopedia is both accessible and comprehensive enough for both the serious stargazer and the professional astronomer.