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Raynor Lockwood Duncombe was born on March 3, 1917, in Bronxville, NY, and raised in Newtown, Connecticut. He died on July 12, 2013 in Austin, Texas. He received a B.A. degree in English Literature and Astronomy from Wesleyan University in 1940, a M.A. degree in English Literature from the University of Iowa in 1941. He joined the staff of the U. S. Naval Observatory (USNO) in early 1942, serving in the 6 Inch Transit Circle Division and then transferring to the Nautical Almanac Office (NAO) in 1946, due to his interest in using the punched card equipment, which Wallace Eckert brought for automating the publications. In 1948 he was detailed for six months to Yale University to set up their computer laboratory, and allowed to take some courses. He then was a research associate while taking graduate studies at Yale University in 1948-49 and 1951-2, and received a Ph.D. in astronomy from Yale University in 1956.
In the NAO he was Assistant Director for Research from 1958 to 1962 and Director from 1963-1975. As director he was responsible for all the USNO publications, including the American Ephemeris and Nautical Almanac, The Nautical Almanac, The Air Almanac, and The Astronomical Phenomena. He was also responsible for all the USNO computer equipment. He participated in the application of punched card equipment and the introduction of computers for astronomical computations from the 1940s to the 1970s. In 1975 he retired from the U.S. Naval Observatory and joined the faculty as a professor in the Department of Aerospace Engineering and Engineering Mechanics at the University of Texas at Austin, where he taught his course, “Determination of Time,” until May, 2012.
In the 1940s Ray wrote papers on occultations of stars by the Moon and on variable stars. He then conducted research in the dynamics of the solar system and the fundamental reference system. His dissertation was “The Determination of the Corrections to Newcomb’s Theory of the Motion of Venus.” This was part of the effort by Gerald Clemence, Wallace Eckert, Dirk Brouwer, and Paul Herget to update the ephemerides of the planets and the Moon. He also studied the motion of Mars, Ceres, Pallas, Juno, and Vesta. He advised a number of students on the determination of the reference system from minor planet observations. He was one of the international leaders in the planning of the transition from the Newcomb based reference system to a modern reference system, introduced in 1984. He did research in celestial navigation and the preparation of Sight Reduction Tables. He was a member of the Astrometry Team of the Hubble Space Telescope (HST) and participated in astrometric studies using the HST. His research resulted in over 125 papers.
He, along with Herget and Clemence, was a consultant for the Vanguard, Mercury, Gemini, and Apollo Projects and the US Navy Space Surveillance System. After the launch of Sputnik I, which was transmitting at 20 and 40 megahertz and not at the international agreement frequency of 103 megahertz, the only US observations were from a horizon surveillance radar. He did a graphical solution of the orbit on a drawing table for the first US determination of the orbit of Sputnik.
He was an associate editor of the Astronomical Journal and Fundamentals of Cosmic Physics, and Executive Editor of Celestial Mechanics. He was president of IAU Commission 4 and the Institute of Navigation, Chairman of the AAAS Engineering Section, and founding chairman of the AAS Division on Dynamical Astronomy. He was a delegate to the CCIR in 1970 -78.
He was a fellow of the American Astronomical Society, American Association for the Advancement of Science, and Royal Astronomical Society, and an Associate Fellow of the American Institute of Aeronautics and Astronautics. He was a member of the Institute of Navigation, International Astronomical Union, International Association of Institutes of Navigation, Association of Computing Machinery, Washington Philosophical Society, New York Academy of Science, Washington Academy of Science, Sigma Xi, Sigma Gamma Tau, and Celestial Mechanics Institute. He was listed in Who’s Who in the World 3rd edition and many other specific Who’s Who editions.
He received the Norman P. Hays Award of the Institute of Navigation, and the Navy Senior Executive Award. Minor planet 3368, Duncombe, is named in his honor.
With Julie, his wife of over 50 years, he entertained many colleagues. He is survived by his son, Ray, and his wife, Jan, two grandchildren, Christina and Ray, his wife, Heidi, and two great grandchildren, Zack and Ava. He was a wonderful mentor and friend to many, including me. As many said, and my wife and I agree, we were blessed to have known Ray.
Obituary written by: P. Kenneth Seidelmann (Univ. of Virginia)
BAAS Citation: BAAS, 2013, 45, 011