Containing over 2,400 entries, this wide-ranging dictionary encompasses all aspects of classical and modern astronomy and gives the names of constellations, stars, galaxies, asteroids, comets, nebulae, and observatories. Entries on telescopes and space missions show how astronomers have opened new windows on the universe, while exact definitions of terms used in modern astrophysics and cosmology allow access to the most-up-to-date research.