Astronomical Applications Department
of the U.S. Naval Observatory
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This US Naval Observatory Website is undergoing modernization and will be offline starting Thursday, 24 October 2019. The expected completion of work and return of service is estimated as 30 April 2020. Please visit and submit a Requirements Form to the USNO PAO if the information you are seeking is not accessible via another means.

Welcome to the web pages of the Astronomical Applications Department of the U.S. Naval Observatory. Our products - almanacs, software, and web services - provide precise astronomical data for practical applications, serving the defense, scientific, commercial, and civilian communities.
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, research reports Computer almanac for PCs and Macs, and more Information about the department and its history
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