United States Naval Observatory

The U.S. Naval Observatory (USNO) provides a wide range of astronomical data and products, and serves as the official source of time for the U.S. Department of Defense, and a standard of time for the entire U.S. Founded in 1830 as the U.S. Navy Depot of Charts and Instruments, USNO is recognized as the world's foremost authority on spatial and temporal reference frames. USNO is headquartered in Washington, D.C., and operates a dark-sky observing station near Flagstaff, Arizona (NOFS). It also has a small detachment activity, the Alternate Master Clock facility (AMC), located at Schriever Space Force Base in Colorado Springs, Colorado.