We regret to announce the passing
of U.S. Naval Observatory astronomer
and I.A.U. Commission 26 member
Richard L. Walker.
Dick was born March 9, 1938 in Hampton, Iowa and earned degrees in both astronomy and physics from the University of Iowa. He worked for the Naval Observatory (both in Washington, DC and Flagstaff, Arizona) for over 30 years, before his retirement in 1999. From the mid 1960s through the late 1970s much of Dick's time was devoted to the measurement of binary stars. He cut his teeth with the 12" refractor in Washington and later observed with the 26" refractor. After going to Flagstaff he observed double stars with both the 40" and 61" reflectors as well as making many trips to Lick Observatory to work with the 36" Clark Refractor there. During this time he consulted with Charles Worley (who was observing on the 26") to make sure time was well spent examining doubles which could not be observed in Washington. This period of observing, overlapping with the early years of speckle interferometry, were important times for visual micrometry to verify the accuracy of the newer technique. Dick had access to the largest telescope used for micrometry at the time, and thus, his observations were very important to ascertain the veracity of this new technique. On all of these instruments he worked with the historic Clark II micrometer, used previously by Asaph Hall, T.J.J. See, and William Markowitz.
He was a studious and very careful observer of doubles and over those years made over 8000 measures of doubles resulting in almost 3000 mean positions. While contributing to the measures of known systems for orbital analysis, he discovered 22 pairs, mostly additional components to known systems. Ascertaining the physicality of the new pairs and determining the distribution of Nsystems/Nstars has important consequences for stellar evolution theory. He also calculated orbits to four fast moving pairs. While these orbits are not the orbits "of choice" today, it was Dick highlighting the rapid motion of these systems that resulted in them being placed on many programs and has led to the more definitive orbits of today.
Dick also ventured into other areas of astronomy, among them discovering the moon of Saturn, Epimetheus, in December 1966, with the USNO Flagstaff Station, 61" astrometric reflector.
Observation of Walker 9, made October 4, 2001, with the 26" Clark Refractor and the USNO speckle camera.
Dick Walker died Wednesday, March 30, 2005, after having been in declining health for the last couple years. He is survived by his wife, Patricia, six children, ten grandchildren, and two great-grandchildren, who were no doubt a great inspiration in his many interests, among them, writing children's literature. He will be sorely missed by his many friends and colleagues.