Astronomy is expanding almost as rapidly as the universe itself, and the proliferating scientific jargon can sometimes baffle even the most dedicated amateur. Now, in some 4,000 concise, up-to-date entries, this dictionary cuts a clear path through the maze of complex technical language, offering full, clear definitions drawn from all aspects of astronomy. Compiled by Ian Ridpath, a fellow of the Royal Astronomical Society, and an expert team of contributors, A Dictionary of Astronomy contains the most recent entries from astrophysics and cosmology to galaxies and time.Here are succinct definitions for the Big Bang theory, comets, eclipses, Magellanic Clouds, Mars, quasar, relativity, and variable stars. Entries on telescopes and other measuring devices, observatories, space missions, and recently named Solar System objects show how astronomers have explored the universe. The Dictionary also provides biographical entries on eminent astronomers from Copernicus to Edwin Hubble.From black hole to white dwarf, and from spiral galaxies to solar waves, A Dictionary of Astronomy opens a window on the universe for amateur astronomers everywhere.