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The USNO websites aa.usno.navy.mil, ad.usno.navy.mil, aristarchus.usno.navy.mil, maia.usno.navy.mil, rorf.usno.navy.mil, and toshi.usno.navy.mil are undergoing modernization efforts. The expected completion of the work and return of service is estimated as 30 April 2020. Please submit a requirements form to the USNOPAO if the information you are seeking is not accessible via other means.
 

Astronomical Applications

Quartermaster Seaman with Sextant

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 https://www.usno.navy.mil/USNO/about-us and submit a Requirements Form to the USNO PAO if the information you are seeking is not accessible via another means.

 

 


Data Services

Sun and Moon rise and set times, Moon phases, eclipses, seasons, positions of solar system objects, and other data

Astronomical Information Center

Background information on common astronomical phenomena, calendars and time, and related topics

Almanacs and Other Publications

Astronomical and navigational almanacs, special publications, research reports

Software Products

Computer almanac for PCs and Macs, and more

For DoD Users

USNO Master Clock Time
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