Theodore Dunham, Jr.
In 1932, while on the staff of the Mount Wilson Observatory, Pasadena, California, Dr. Dunham discovered that the atmosphere of Venus is principally composed of carbon dioxide. At that time, astronomers tended to believe that Earth and Venus had similar atmospheres, but Dr. Dunham (with Walter S. Adams) found some unusual features in the spectrum of radiation from Venus. Dr. Dunham demonstrated that if light were sent through a long pipe containing compressed carbon dioxide, the same spectrum could be reproduced on Earth, indicating that carbon dioxide, under higher pressure than the Earth's atmosphere, had been observed in the atmosphere of Venus. This conclusion was dramatically confirmed 35 years later in measurements transmitted from U. S. and Soviet spacecraft.
Dr. Dunham's principal research activities included development of Coude spectrographs at Mount Wilson Observatory and at Mount Stromlo Observatory in Australia, introduction of the Schmidt camera in spectroscopy, studies of stellar atmospheres and interstellar material, studies of planetary atmospheres, development of photoelectric detectors for spectroscopy, and application of physical methods for research in medicine and surgery.
Dr. Dunham's interest in astronomy began early, and by the age of 17 he had built an observatory on the grounds of his family's cottage in Northeast Harbor, where his father practiced medicine in the summers.
He was born December 17, 1897, in New York City, the son of Theodore Dunham and Josephine Balestier Dunham. He prepared at St. Bernard's School and the Browning School, New York City, and received an A.B. summa cum laude in 1921 from Harvard concentrating in chemistry.
Throughout his career, he followed interests in medicine, physics and astronomy. He received an M.D. from Cornell University in 1925 and an A.M. and Ph.D. in physics in 1926 and 1927 from Princeton University.
For his Harvard College Fiftieth Reunion in 1971, he wrote: "I have gained much by stimulating contacts with many leaders in research, who combined extraordinary insight with unusual human qualities. I am thinking in particular of Theodore W. Richards in Chemistry, James Ewing in Pathology, and George Ellery Hale in Astronomy."
Dr. Dunham was a staff member of Mount Wilson Observatory from 1928 to 1947. During World War II from 1942 to 1946, he was Chief of the Optical Instrument Section (16.1) of the Office of Scientific Research and Development under George Harrison and Vannevar Bush. He then spent several years applying physical methods to medical research, first from 1946 to 1948 as a Warren Fellow in Surgery at Harvard Medical School, and then from 1948 to 1957 at the School of Medicine and Dentistry and the Institute of Optics at the University of Rochester, where he developed instrumentation for spectrophotometric analysis of small regions of biological cells.
In 1957, he joined the faculty of the Australian National University in Canberra, where he designed and installed a spectrograph at the Mount Stromlo Observatory for use with its 74-inch telescope in studying the composition of the stars of the Southern Hemisphere. From 1965 to 1970 he was a Senior Research Fellow at the University of Tasmania, Australia.
After returning to the United States in 1970, he resumed his earlier association with the Harvard College Observatory.
Dr. Dunham was Scientific Director of the Fund for Astrophysical Research from its founding in 1936. At the time of his death, he had just completed designing and supervising the construction of a computer-guided telescope of a new alt-alt design. It was installed and dedicated at the new Science Center of the University of Chicago in 1985.
Dr. Dunham was the author of over 50 scientific articles and a member of many scientific organizations, including the American Physical Society, the Royal Astronomical Society, the American Astronomical Society, the American Association of Variable Star Observers, the Astronomical Society of the Pacific, the American Optical Society, the New York Academy of Sciences, and the International Astronomical Union (in which he was a member of Commissions on Instruments, Stellar Spectra and Interstellar Material).
On June 21, 1926, he married Miriam Phillips Thompson, daughter of Mr. and Mrs. William G. Thompson of Boston and South Tamworth, New Hampshire, a granddaughter of the Rev. Dr. William Reed Huntington. He was survived by his wife and their children, Theodore Dunham, III, and Mary Huntington Dunham.