Edited by renowned author and broadcaster Ian Ridpath, with the help of over 20 expert contributors, the second edition of this highly popular dictionary contains over 4,200 up-to-date entries on all aspects of astronomy. Readers will find a galaxy of informative, vividly written entries on everything from space exploration and the equipment involved, to astrophysics, cosmology, and the concept of time. The dictionary also features biographical entries on eminent astronomers--ranging from Galileo to Edwin Hubble--as well as world-wide coverage of observatories and telescopes. Appendices include tables of Apollo lunar landing missions, and the constellations. Entries are supported by numerous tables and diagrams. The text has been fully revised and updated for the second edition, and includes information on new space missions, both those planned for the future and those that have recently come to fruition (such as the Huygens Probe of Saturns moon Titan). It also boasts entry-level Internet links (accessed via a regularly updated website), and in-depth features on topics such as the Big Bang, Dark matter, and Gamma-ray bursts.