logo

Video encyclopedia

United States Naval Observatory

1:17

An inside look at the vice president's residence

1:25

United States Naval Observatory

3:41

Kamala Harris boards Marine Two and departs the US Naval Observatory November 1, 2021

3:01

Do You Know Where the Vice President Lives

1:04

German Chancellor Angela Merkel Arrives at U.S. Naval Observatory for Breakfast with VPOTUS Harris

The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation and Timing (PNT) for the United States Navy and the United States Department of Defense. Located in Northwest Washington, D.C. at the Northwestern end of Embassy Row, it is one of the pre-1900 astronomical observatories located in an urban area; at the time of its construction, it was far from the light pollution thrown off by the (then-smaller) city center. Former USNO director Gernot M. R. Winkler initiated the "Master Clock" service that the USNO still operates, and which provides precise time to the GPS satellite constellation run by the United States Air Force. The USNO performs radio VLBI-based positions of quasars with numerous global collaborators, in order to produce Earth Orientation parameters.
  • History 

  • Departments 

  • Time service 

  • Publications