Walt Mitchell died 26 July 1996 in a nursing home near Columbus, Ohio. He had battled bravely for several years against complications resulting from the AIDS virus. He kept his spirits high to the end.
Walt was born (16 November 1925) in Franklin, Massachusetts, where his father was an insurance broker. He served in the army infantry during World War II, rising through the ranks to 2nd Lieutenant. He earned the Purple Heart for injuries received in France. Following the war, he entered Tufts College, where he earned his BS degree in 1949. He received the MS degree from the University of Virginia in 1951 and his PhD from the University of Michigan in 1959, with a thesis entitled "The Center-Limb Variation of the Intensities of Selected Solar Lines."
While at Michigan, Mitchell became involved in the solar spectroscopy program, which was carried on in part at the Snow Telescope at the Mount Wilson Observatory. This program, initiated by Leo Goldberg, Orren Mohler, and others, involved the long-term use of the Snow Telescope by a number of young students who later became distinguished solar astronomers, and Walt was among this group. He spent several summers obtaining high disperson solar spectra in the visible and infrared at Mount Wilson in the 1950's and continued his work in this area at the Snow Telescope later when he was on the Ohio State faculty. Walt published a number of papers on solar spectroscopy, including a UV solar spectrum atlas. He was interested in the solar cycle variation of spectral lines, especially the H and K lines of ionized calcium, and did much important work in this area. He also made contributions in the area of solar limb darkening in the infrared and ultraviolet.
During his time spent at Mount Wilson, Mitchell became interested in the outdoors and did a great deal of hiking and camping. He served as a tour leader for Sierra Club hikes, especially in the Death Valley area. One of his favorite hikes was to Telescope Peak.
Walt joined the astronomy faculty of Ohio State University in 1957, after serving a year as Assistant Professor in the Astronomy Department of Brown University. At Ohio State, he rose to the rank of Professor by 1968 and retired in 1991. He took a great interest in undergraduate education and was for some time the director of the planetarium at Ohio State, as well as being an active member of the Great Lakes Planetarium Association, the International Planetarium Society, and the Association of Astronomy Educators. He also continued his interest in high-dispersion solar spectroscopy after his retirement and continued his summer observations at Mount Wilson.
In more recent years, he became involved with the Consortium for Undergraduate Research and Education in Astronomy (CURIA), led by Joe Snyder at Oberlin College. This organization provides hands-on experience and instruction in solar observing for undergraduates each summer at the Snow Telescope. Walt served as an instructor in this program for many summers, up until the year before he died. His professional papers and library were distributed to family, friends, the Astronomy Department at Ohio State, and Perkins Observatory.
Walt is survived by two sisters, Jerane DiCostanzo in New York City and Jeanette Harding in Franklin, Massachusetts, five nieces and a nephew. All those who came into contact with Walt Mitchell knew him to be a kind and considerate man. One friend told me that she once brought a cake to an astronomical outing. The cake had turned out badly and really didn't taste very good. In order not to hurt his friend's feelings, Walt ate two pieces. This is typical of his thoughtfulness, and it is a story that will ring true to anyone who knew him. He was an inspiring teacher and a diligent researcher. He was self-effacing, but he had a subtle and infectious sense of humor. We will all miss Walt; the world is a little worse off without him.
Photo (available in PDF version): Walter E. Mitchell, Jr. in 1959 (courtesy The Ohio State University Archives).