As part of his continuing Phd studies May designed and built a zodiacal light observation hut on the site of what is now the huge Observatory del Tiede in Tenerife, a facility now internationally shared amongst astronomers. From there May pursued his investigations into the motions of interplanetary dust. He remains in touch with various astronomers in The Observatory.Since I am a BIG fan of his old band and especially his guitar-playing (had "Good Old Fashioned Lover Boy" on repeat all day yesterday just for the guitar parts), I think Brian May deserves to be blogrolled :) (See his blog entries from Dec '05 where he talks about the recording of Bohemian Rhapsody.)
May is also regarded as an expert in the field of Victorian Stereoscopic Photography. He contributed some of his major collection to a Victoria and Albert Museum exhibition earlier this year, and is currently working on a book on TR Williams, a prominent stereo photographer of the 1850's.
Oh, and do read this unbelievably prosaic entry for "Good Old Fashioned Lover Boy" in Wikipedia. That second 'graf is duller than cricket commentary delivered by a radio announcer on Valium.