abstract: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 U.S.
Close tothe BritishEmbassyisthe United StatesNavalobservatory. Astronomers use theobservatory to study the positionsandmovementsof theEarth, sun, moonandother objects in space.