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
William Lowell Putnam for both Percival Lowell and the Lowell Observatory as well as working as a partner at the well-regarded law firm of Putnam, Putnam and Bell. Putnam's role in Lowell Observatory's history begins when Percival Lowell succumbed to severe nervous exhaustion in 1897. At this time, Putnam stepped in as the Observatory's trustee with A.E. Douglass serving as Director. Since Putnam's understanding of astronomy was minimal, he left many of the decisions about the operation of the Observatory to Douglass and contented himself with handling the Observatory's finances. As temporary trustee, he felt that it was not his place to make