Arizona is home to several observatories, including this one founded by Percival Lowell in 1894. Flagstaff's observatory boasts three telescopes, the oldest of which is the Clark Telescope, dating from 1896, which is operated manually. The most famous is the Pluto Dome, through which Pluto was discovered in 1930. The observatory and the library are open as part of a guided tour, while the exhibitions and the Space Theater can be explored independently. The park offers fine views of Flagstaff.