An observatory at an altitude of 2210 m on Mars Hill, Flagstaff, Arizona, founded in 1894 by P. Lowell. Its main telescope is the 4.3-m Discovery Channel Telescope, opened in 2015 on an outstation at Happy Jack, 65 km southeast of Flagstaff. Notable instruments at Flagstaff are a 24-inch (0.61-m) refractor installed by Lowell in 1896, and the 0.33-m astrograph with which Pluto was discovered. In 1961 a dark-sky outstation was opened on Anderson Mesa, 19 km southeast of Flagstaff, altitude 2200 m. This contains the 1.83-m Perkins reflector operated jointly with Boston University, moved there from Ohio in 1961; the 1.1-m John S. Hall reflector opened in 1968; a 0.8-m reflector; and a 0.6-m Schmidt used for the Lowell Observatory Near-Earth Object Search. The Navy Precision Optical Interferometer (NPOI), a joint project of the Naval Research Laboratory, the US Naval Observatory, and Lowell Observatory, began operation on Anderson Mesa in 1996, performing high-resolution astrometry and imaging.

http://www.lowell.edu/ Official observatory website.