Compiled with the help of a team of expert contributors under the editorship of renowned author and broadcaster Ian Ridpath, the third edition of this dictionary covers everything from space exploration and the equipment involved to astrophysics, cosmology, and the concept of time. The dictionary also includes biographical entries on eminent astronomers, as well as worldwide coverage of observatories and telescopes. Supplementary material is included in the appendices, such as tables of Apollo lunar landing missions, the constellations, and planetary data, and numerous other tables and diagrams complement the entries.