Lowell Observatory, located in Flagstaff, Ariz., is a privately owned astronomical research institution. The observatory was founded in 1894 by Percival Lowell, a Boston mathematician. Best known for the discovery of Pluto, Lowell Observatory is also where astronomer V.M. Slipher gathered the first evidence that the universe is expanding. Each year, more than 70,000 people visit the observatory to learn about astronomy by participating in multimedia programs, private and school programs, special events, and other educational activities. The observatory features a regular program of telescope viewing. Lowell Observatory s library has a wide collection of biographies and bibliographies, historical logbooks, manuscripts, working paper, research contracts and historical photographs.