Compiled with the help of over 20 expert contributors under the editorship of renowned author and broadcaster Ian Ridpath, the third edition of A Dictionary of Astronomy covers everything from space exploration and the equipment involved, to astrophysics, cosmology, and the concept of time, in over 4,300 entries. 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, planetary data, and numerous other tables and diagrams complement the entries. The entries have been fully revised and updated for this edition, and more than 100 new entries have been added to reflect the recent developments within the field of astronomy, including Bennu, Euclid, Mars Orbiter Mission, and slowly pulsating B star. A Dictionary of Astronomy is an invaluable reference source for students, professionals, amateur astronomers, and space enthusiasts.