A comprehensive and authoritative A-Z guide to the Universe, with more than 3,000 fully cross-referenced articles on all aspects of astronomy and astrophysics. It is illustrated with 500 colour photographs and explanatory diagrams, as well as star maps by renowned celestial cartographer Wil Tirion. There are special features on each of the constellations and tables listing brightest stars, nearest stars, Messier objects, Caldwell objects, and surface features of the Moon and terrestrial planets. Written by more than 100 leading astronomers from the world's universities and observatories, it is comprehensive, authoritative and accessible. The best A-Z encyclopedia for enthusiastic sky watchers. Over 500 colour photographs, star maps and explanatory diagrams.