Lowell Observatory

Lowell Observatory is a 100+ year old observatory in Flagstaff, Arizona, with historical, educational, and research telescopes. Among its research telescopes:

• Lowell Discovery Telescope (LDT) (4.3 m telescope, formerly the Discovery Channel Telescope, DCT).
• Perkins Telescope (180 cm, 72 in).
• Hall Telescope (110 cm, 42 in).
• Navy Precision Optical Interferometer (NPOI) (optical interferometer).

Among its historical telescopes is the Pluto Discovery Telescope (aka Pluto Telescope, earlier the Lawrence Lowell Telescope), an astrograph used to discover Pluto after being acquired for the purpose. It was later used for the Lowell Proper Motion Survey.