This fully updated and revised dictionary covers all aspects of astronomy, from telescopes to planets, equations to astronomers, stars to comets. It includes recent missions, discoveries and changes in technology. The dictionary clearly explains complex terms and includes illustrations to help explain complex ideas and terms. Over 2,000 entries; Comprehensive coverage of all aspects of astronomy; Includes illustrations and diagrams to help explain complex terms; Handy, compact format; Clear layout, with all terms defined simply and concisely.