FRSSAf was a British South African optical astronomer who was Emeritus Distinguished Professor of natural philosophy at the University of Cape Town.
[1] He didn't pass his eleven-plus exam, failing in mathematics, but was nonetheless admitted to the East Grinstead County Grammar School on the recommendation of his teacher.
[1][3][4] Warner remained at UCL for postgraduate studies, completing a PhD in astronomical spectroscopy in 1964 titled Abundances in Late type Stars.
[1] Warner became a postdoctoral researcher at UCL, before being awarded a Radcliffe-Henry Skynner Fellowship at Balliol College, Oxford, though the university didn't have its own observatory.
[6][1] He also worked with his colleagues Ed Nather and David Evans in developing the new field of high-speed photometry for studying variable stars and measuring stellar radii by observing lunar occultations.