Astronomer; Historian; Educator
Mathematical and Physical Sciences
Astronomy, Astrophysics, and Earth Sciences
Early astrophysical research centeredon the computation of model stellar atmospheres, including the first calculations for the solar atmosphere taking into account rocket and satellite ultra-violet observations. Since 1971 his research has concentrated on the history of astronomy, especially Copernicus, Tycho Brahe, and Kepler, although his historical investigations range from Ptolemy to modern astrophysics. A bibliophile and collector, he has compiled an annotated census of 598 sixteenth-century copies of Copernicus' De revolutionibus. In recent years he hsa been an active proponent of the science and religion dialogue.