Prepared in cooperation with the Royal Greenwich Observatory, Her Majesty's Nautical Almanac Office. Provides information about sunrise and sunset, moonrise and moonset, stars and other astronomical phenomena. Data are expressed in the scale of universal time, also known as Greenwich mean time.

Prepared jointly with Her Majesty's Nautical Almanac Office, United Kingdom Hydrographic Office. Designed in consultation with other astronomers of many countries. Provides current, accurate astronomical data for use in the making and reduction of observations and for general purposes. The Astronomical Almanac Online extends the printed version by providing data best presented in machine-readable form. Online data are provided for several years. Contains data for astronomy, space sciences, geodesy, surveying, navigation, and other applications. Also used for navigation by air and water.The Astronomical Almanac is a joint publication of the U.S. Nautical Almanac Office, United States Naval Observatory (USNO), in the United States and Her Majesty's Nautical Almanac Office (HMNAO), United Kingdom Hydrographic Office (UKHO), in the United Kingdom. This annual publication contains precise ephemerides of the Sun, Moon, planets, and satellites, data for eclipses and other astronomical phenomena for a given year, and serves as a world-wide standard for such information.

Astrometry encompasses all that is necessary to provide the positions and motions of celestial bodies. This includes observational techniques, instrumentation, processing and analysis of observational data, reference systems and frames, and the resulting astronomical phenomena. Astrometry is fundamental to all other fields of astronomy, from the pointing of telescopes, to navigation and guidance systems, to distance and motion determinations for astrophysics. In the last few decades, new observational techniques have enabled improvements in accuracy by orders of magnitude. Starting from basic principles, this book provides the fundamentals for this new astrometry at milli- and micro-arcsecond accuracies. Topics include: basics of general relativity; co-ordinate systems; vectors, tensors, quaternions, and observational uncertainties; determination and use of the celestial and terrestrial reference systems and frames; applications of new observational techniques; present and future star catalogues and double star astrometry. This comprehensive reference will be invaluable for graduate students and research astronomers.

America's finest science writer describes a major revolution sweeping astronomy, as amateur astronomers, in global networks linked by the Internet, make discoveries that are changing the knowledge of the universe. Illustrations.