The United States Naval Observatory Flagstaff Station (NOFS), is an astronomical observatory near Flagstaff, Arizona, USA. It is the national dark-sky observing facility for the U.S. Department of Defense, under the United States Naval Observatory (USNO). NOFS and USNO combine as the Celestial Reference Frame manager for the U.S. Secretary of Defense. The Director of NOFS (an Echelon Five Naval command and installation) is also identified as Commander, Task Force Element 80.7.3.1 under the CNMOC operational infrastructure.