The United States 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 United States. The United States Naval Observatory is a fourth echelon operational command reporting to the Commander, Naval Meteorology and Oceanography Command. The Observatory's headquarters are located in Washington, DC, with field activities located at the Naval Observatory Flagstaff Station (NOFS) in Flagstaff, AZ and at Schriever Space Force Base near Colorado Springs, CO.