Bob was born near Newport News, VA. His father was an archaeologist, and Bob often recounted going on "digs" with his family in the States. He attended schools in Richmond, VA, and graduated from Thomas Jefferson High School there in 1960. Afterwards, he went to Swarthmore College, (previously attended by his mother and aunt and uncle). Bob stated that he was interested in astronomy from such an early age that he couldn't remember the onset. At Swarthmore he naturally came under the influence of Peter van de Kamp and Sara Lippincott of Sproul Observatory, and consequently was well-schooled in the classical techniques of photographic astrometry, including observing with the 60cm refractor, as well as measuring and reducing the results. His first published scientific paper (jointly with van de Kamp) was a study of the quintuple system Xi Scorpii.
In 1962 Bob accompanied van de Kamp to a summer institute at Wesleyan University, where he performed the duties of a teaching assistant, and where he met W.H. Jeffreys, then a graduate student, who was soon to become Bob's thesis advisor.
Following his 1964 graduation from Swarthmore with a B.A. in Physics, Bob enrolled in the graduate program in astronomy at the University of Texas in Austin. There his interests quickly turned to theoretical dynamical astronomy under the tutelage of Jeffreys. While Bob retained a strong interest in this subject throughout his entire career, he made many contributions to other astronomical fields, and, in addition to Jefferys, was especially influenced at Texas by H. Smith and D. Evans.
Following the award of his doctorate in 1967, Bob applied for a job with the Nautical Almanac Office of the U.S. Naval Observatory, because, as he explained, that organization represented interests closest to his own. Unfortunately, the Nautical Almanac Office had no positions available, but V.M. Blanco, then director of the Astrometry and Astrophysics Division, quickly offered him a position. He remained in this organization and its successors throughout the rest of his career. Bob initially took part in the routine photographic double star program, and also observed asteroids with the 38cm astrograph.
Bob was married in 1976 to Betty-Jean Maycock, who holds a doctorate from the University of Maryland, as well as being an Olympic gymnast (Rome, 1960), and a gold medalist in the goodwill competition in Moscow in 1961. Two daughters, Amy and Ann, were born of the union.
Undoubtedly, if asked, Bob would point to his work in dynamical astronomy as being not only his most significant contribution, but also as being the most fun. Beginning with his very first paper, and continuing until nearly his last, Bob was concerned with the dynamical interactions in multiple star systems. The extensive numerical integrations required by this work entailed use of a great amount of computer time on the slow machines then available. Consequently, Bob often was found loading programs or retrieving results at all hours of the night or day, as well as on weekends and holidays.
Within a few years of his arrival, Bob was put in charge of the plate measurements and reductions for the extensive parallax program being carried out with the 155cm reflector in Flagstaff, and therefore was a coauthor of many series of publications dealing with parallaxes and proper motions of faint stars. Today this effort largely defines both the lower main and white dwarf sequences of the HR diagram. An important by-product of this work was the detection of a number of unseen companions through their perturbations of the visible stars.
Considerations on the stability of the solar system led Bob to collaborate with T.C. Van Flandern in studies of the dynamical evolution of its satellites, and to an eventual search for "Planet X", conjectured to lie beyond Pluto and to be responsible for small, unexplained, residuals in the orbits of Uranus and Neptune. Late in his career Bob seemed quite skeptical of such an object, however. Nevertheless, the program instituted at Flagstaff to photograph the outer planets and their satellites led to the spectacular discovery in 1978, by J.W. Christy, of Pluto's satellite. Bob's inspired guess that the period of revolution matched the already known period of light variation resulted in rapid determination of the orbital elements, and hence the mass of both planet and satellite.
Bob's eclectic astronomical interests led to papers on galaxies, sunspot areas, solar-wind flows, archaeoastronomy, earth tides, distribution of comet orbits, positions of minor planets, and even the geodetic coordinates of the Cerro Tololo Inter-American Observatory.
He served as a joint editor of four books, was a member of the AAS, the IAU (where he served on four commissions), the Planetary Society, and the Society of Sigma Xi. He also served on the astrometry team for the International Halley Watch, and on the local organizing committee for the 20th General Assembly of the IAU.
Although he accepted administrative duties in his later years, Bob was not very comfortable doing bureaucratic work. He was much happier doing science, and was always a cheerful and helpful influence on his colleagues. He was a popular speaker about astronomy in his local school system, as evinced by the many teachers from there that attended his funeral. Those of us who worked with him know we were privileged, and we shall miss him.
Charles E. Worley
U. S. Naval Observatory