(Were you looking for Dave Clement the filker)
Dave Clements is a Senior Lecturer in Astronomy at Imperial College, London. Introduced to fandom through ICSF he chaired Picocon 4 and was on the committee of Eastercon, Illumination. He's run the Science Programme at various Worldcons, including Anticipation, MidAmeriCon 2, and Worldcon 75 and worked with John Bray on the Intersection and Loncon 3 ones.
He runs the Science for Fiction Writers presentation series where science fiction authors can hear about cutting edge science from practising scientists.