Percival Lowell Milan Observatory. In 1894 Lowell chose Flagstaff, Arizona Territory, as the home of his new observatory. At an altitude of over , with few cloudy nights, and far from city lights, Flagstaff was an excellent site for astronomical observations. This marked the first time an observatory had been deliberately located in a remote, elevated place for optimal seeing. For the next fifteen years he studied Mars extensively, and made intricate drawings of the surface markings as he perceived them. Lowell published his views in three books: "Mars" (1895), "Mars and Its Canals" (1906), and "Mars As the Abode of Life"
Lowell Observatory Flagstaff. Also located on the Mars Hill campus is the Pluto Discovery Telescope, used by Clyde Tombaugh in 1930 to discover the dwarf planet Pluto. Lowell Observatory currently operates four research telescopes at its Anderson Mesa dark-sky site, located southeast of Flagstaff, including the Perkins Telescope (in partnership with Boston University) and the John S. Hall Telescope. Lowell is a partner with the United States Naval Observatory and Naval Research Laboratory in the Navy Precision Optical Interferometer (NPOI) also located at that site. The Observatory also operates smaller research telescopes at its historic site on Mars Hill and in Australia