astronomical applications department
The Astronomical Applications Department of the U.S. Naval Observatory computes, from fundamental astronomical reference data, the position, brightness, and other observable characteristics of celestial bodies, as well as the circumstances of astronomical phenomena. Our products -- almanacs, software, and web services -- provide precise astronomical data for practical applications, serving the defense, scientific, commercial, and civilian communities. The department also conducts scientific studies in celestial mechanics, navigation, and positional astronomy to enable it to meet future needs.
Sun and Moon rise and set times, Moon phases, eclipses, seasons, positions of solar system objects, and other data.
Background Information on common astronomical phenomena, calendars and time, and related topics.
Astronomical and navigational almanacs, special publications, and research reports.
Computer almanac for PCs and Macs, and more.
Information about the Department and its history.