Lowell Observatory operates the 72-inch Perkins, 42-inch Hall, 44-cm Lowell Observatory Near Earth Object Survey (LONEOS) Schmidt, and a 31-inch telescope at its Anderson Mesa site, 15 miles southeast of Flagstaff. With the U.S. Naval Observatory, Lowell jointly operates the Navy Prototype Optical Interferometer, also at Anderson Mesa. The 12,000-ft (3600-m) volcanic complex of the San Francisco Peaks dominates local scenery.