Lowell (Martian crater) Lowell (Martian crater) The Lowell Crater is a large impact crater on Aonia Terra in the Thaumasia quadrangle of Mars. The crater is about 203 kilometers (127 miles) in diameter. Lowell Crater has a ring of mountains on its floor which gives it a sort of bull's eye appearance. Its nearby features include the craters Slipher to the north, Douglass to the east, and Coblentz to the southwest, the small mountain Aonia Mons to the west, and Aonia Planum to the southeast. Lowell Crater is named for Percival Lowell who built the Lowell Observatory in Flagstaff, Arizona, in 1894, and
Lowell Observatory first trustee was Lowell's third cousin Guy Lowell (1916–1927). Percival's nephew Roger Putnam served from 1927 to 1967, followed by Roger's son Michael (1967–1987), Michael's brother William Lowell Putnam III (1987–2013), and current trustee W. Lowell Putnam. The observatory operates several telescopes at three locations in the Flagstaff area. The main facility, located on Mars Hill just west of downtown Flagstaff, houses the original Clark Refracting Telescope, which is now used for public education, with 85,000 annual visitors. The telescope, built in 1896 for $20,000, was assembled in Boston by Alvan Clark & Sons and then shipped by train to