Ph.D. in Experimental High Energy Physics, M.I.T. 1972.
As a member of the Solar Physics Group at A.S.&E., he was responsible for all aspects of the Skylab S-054 x-ray telescope data reduction, from calibration and processing of flight film through digitization and analysis of images.
He is presently an Astrophysicist at the Harvard-Smithsonian Center for Astrophysics. He is U.S. Principal Investigator (P.I.) of the Solar-B X-ray Telescope and was P.I. of the Normal Incidence X-ray Telescope (NIXT) and the Tuneable X-ray Imager (TXI) sounding rocket programs. He served as Smithsonian Astrophysical Observatory (SAO) Instrument P.I. for the NASA TRACE satellite and for the new Atmospheric Imager Assembly on NASA's Solar Dynamics Observatory. He has published extensively on the relation between magnetic fields and coronal heating, on magnetic dynamo processes and on activity in the Sun and in solar-type stars; he has also published extensively on hardware and experimental methods for obtaining state-of-the-art observations for coronal studies. He is co-author of the book "The Solar Corona" from Cambridge University Press, and of the trade book "Nearest Star," published by Harvard University Press.