 He then went to Cambridge University for postgraduate work in theoretical astrophysics with Leon Mestel and Donald Lynden-Bell, and completed his doctorate in 1965.Following a postdoctoral appointment at the University of Texas with Gérard de Vaucouleurs, and a research fellowship at Trinity College, Cambridge, he returned to Australia in 1967 as a Queen Elizabeth Fellow at Mount Stromlo.Apart from a year in the Kapteyn Institute in Groningen in 1976 and some occasional absences overseas, he has been at Mount Stromlo ever since.