James Craig Watson
Mitchell was elected Director Emeritus in 1945 with a wealth of academic and scientific honors attributed to him. He was a member of the following societies: National Academy of Sciences (elected in 1933, elected to council in 1940, awarded James Craig Watson Medal in 1948), American Association for the Advancement of Science (Vice-President in 1921), American Astronomical Society (Vice-President 1925–1927), Royal Astronomical Society (fellow and associate), International Astronomical Union (president of Commission on Solar Eclipses and Commission on Stellar Parallaxes and Proper Motions), American Association of University Professors (chairman of Committee A, on Academic Freedom and Tenure), American Philosophical Society, and the American Academy of Arts and Sciences.