Lowell Observatory

Percival observing Mars from the Clark telescope at the Lowell Observatory

Lowell Observatory is an astronomical observatory in Flagstaff, Arizona. It was founded in 1894 by astronomer Percival Lowell.

The observatory operates nine telescopes at two locations in Flagstaff. The facility at Mars Hill houses the site's original 24-inch (.61-meter) refractor telescope, although it's role today is as a public education tool and not research. The telescope, built in 1896 for $20,000, was assembled in Boston by Alvan Clark and then shipped by train to Flagstaff. The telescope is listed as a national historic landmark. The second observation site, at Anderson Mesa, houses four telescopes, including a 72-inch (1.8-meter) Perkins telescope that it shares with Boston University, the 42-inch (1.1-meter) Hall Telescope and the Navy Prototype Optical Interferometer (NPOI).

Notable discoveries

• Evidence for the expansion of the universe was discovered between 1912 and 1915
• The planet Pluto was discovered in 1930 by Clyde Tombaugh.
• The planetary ring system of Uranus observed in 1977

• Lowell Observatory
• Boston University Astronomy website
• Navy Prototype Optical Interferometer