National Astronomical Observatory of Japan
He has been a Visiting Professor at the National Astronomical Observatory of Japan (Nobeyama and Tokyo), an Associate of the European Southern Observatory and has worked for various periods at the California Institute of Technology, the University of Arizona, the Institut d'astrophysique de Paris (France), the Observatoire de Besançon, the Institute of Astronomy, Cambridge (UK) and the Physical Research Laboratory, Ahmedabad (India). He has also been an Adjunct Professor at James Cook University, Queensland, Australia.