With the passing of Donald Alexander MacRae on 6 December 2006 at age 90, the astronomy community lost a visionary scientist and a great educator in the field.
Don MacRae was born in Halifax, Nova Scotia, on 19 February 1916, to Donald Alexander and Laura Geddes (Barnstead) MacRae. His father was originally a classics scholar and preceptor of Greek and Latin at Princeton, but at the time of Don's birth in 1916 he was Dean of the Dalhousie Law School in Halifax. The family moved to Toronto, Ontario, in 1924 when his father joined the faculty of Osgoode Hall Law School in Toronto as a Professor of Law.
After the family moved to Toronto, where he received most of his early education, he obtained his undergraduate degree in Mathematics and Physics in 1937 from the University of Toronto (U of T). He obtained the degree of A.M. in 1940 and of Ph.D. in 1943 from Harvard University under the mentorship of Bart Bok in the field of galactic structure. During his early career he worked briefly at the University of Pennsylvania, Cornell University, and Carbide and Chemical Corporation at Oak Ridge, Tennessee. For Don the latter work was a brief and somewhat uneasy association with the Manhattan Project. In 1946, he obtained a position at Case Institute of Technology (now Case Western Reserve University), where he worked until 1953. In 1953, he accepted a position at the U of T, replacing Ralph Williamson, who had earlier introduced Don to the emerging field of radio astronomy while they both were at Cornell.
Don's primary research field was stellar spectroscopy, but his interests were much broader than this, and he possessed an abiding ability to interest students and faculty in new and emerging ideas. In the early 1960s he developed a strong interest in the nature and origin of the lunar surface, and discussed these extensively with colleagues. Many of his ideas on this subject were later confirmed by the lunar exploration program. Don's continuing interest in radio astronomy led him to introduce this subject area into the Toronto graduate research and teaching curriculum. In collaboration with the Department of Electrical Engineering, he established a radio astronomy observing site at the U of T's David Dunlap Observatory (DDO) in 1956. This was at a time when few astronomers took this subject seriously. The DDO work led to the precise determination of the absolute flux density of Cas A at 320 MHz, a radiometric standard as important today as it was when it was reported in 1963. On behalf of the University of Toronto, he subsequently participated in radio astronomy activity at the National Research Council's (NRC's) new Algonquin Radio Observatory in Algonquin Park. The radio astronomy program that Don established was an early stimulus for the first successful experiment in Very Long Baseline Interferometry in 1967, a collaboration among the University of Toronto, Queen's University, and NRC.
As a teacher, Don was highly regarded by his students, whom he engaged with his characteristic wit and frequent anecdotes. His lectures always were well prepared and organized, and endowed with an underlying belief that the ideas and principles of physics were most easily understood by applying them first to the stars. As an innovative teacher, he was the first professor at Toronto to teach computer programming at the university, recognizing early that students would need such skills in their scientific careers. Similarly, he was a strong advocate for public outreach. He was featured in the Oscar-nominated short film "Universe" produced in 1960 by the National Film Board of Canada. He also was instrumental in the establishment of the McLaughlin Planetarium, which opened in Toronto in October 1968. In honor of his strong record in education, the U of T established an undergraduate scholarship in Don's name in 2003 to reward promising undergraduates in the astronomy program.
In 1965, Don became Head of the Department and Director of the DDO, and continued in these positions for thirteen years. During this period, he presided over a major expansion of the Department, which made it the major center of astronomical activity in Canada. This included the establishment in 1971 of a 24-inch telescope at the site of the Carnegie Southern Observatory at Las Campanas, Chile. The clear weather and excellent seeing conditions at Las Campanas attracted many graduate students to study astronomy at the U of T. It was also used by many astronomers from other institutions.
Don MacRae was an active participant in the establishment of national observing facilities for all Canadian astronomers. He supported the establishment the Algonquin Radio Observatory in the 1960s to serve the growing community in the emerging field of radio astronomy. He participated in the planning and development of the Canada-France-Hawaii-Telescope (CFHT) on Mauna Kea, Hawaii, in the 1970s, and served as one of four Canadian astronomers on the Board of the CFHT Corporation from 1973 to 1979. He was appointed as Board Chair in 1978 for the last year of his term. During the 1970s Don was elected to the Board of Trustees of the Universities Space Research Association (USRA), dedicated to promoting cooperation between NASA and North American universities. He served as USRA Board Chair in 1973. Don was also an active member of the AAS since 1943, and served as AAS Councilor from 1963-1966.
Although Don retired in 1982 and was appointed Professor Emeritus in the Department, he continued his interest in departmental activity for many years after. During the 45 years I knew Don, both as his graduate student 1961-1966, and later as one of his colleagues, I shared with his friends and associates an enduring respect for his wisdom, generosity, sense of humor, powers of observation, and rigorous attention to accuracy and detail. He maintained an abiding ambition to create a leading department and to help in establishing a world-renowned astronomical community in Canada. His legacy is that he succeeded in both areas.
Don enjoyed a life-long interest in photography, carpentry and woodworking. In retirement, he spent a great deal of time on family genealogy. He possessed a strong "do-it-yourself" philosophy, manifested for example in clearing land and building a cottage on Georgian Bay, a family project during his younger years.
Don died in Toronto of natural causes. He is survived by his older sister Jean Borden, and his three sons David, Charles, and Andrew. Don's wife Betty predeceased him by about one year. He is also survived by his four granddaughters and two grandsons, in all of whom he delighted, as well as nieces and nephews who were particularly dear to him.