An observatory on Kitt Peak, Arizona, jointly owned by the University of Michigan, Dartmouth College, the Ohio State University, Columbia University, and Ohio University; the initials MDM arise from the names of the three initial owners, Michigan, Dartmouth, and MIT. The MDM Observatory operates two telescopes: the 2.4-m Hiltner Telescope, altitude 1938 m, opened in 1986, and the 1.3-m McGraw–Hill Telescope, altitude 1925 m, opened at Dexter, Michigan, in 1969 and moved to Kitt Peak in 1975.
http://www.astro.lsa.umich.edu/obs/mdm/ Official observatory website.