Areas of Interest: 

• History of Astronomy
• Scientific Instruments

Research and Teaching: 

I am currently preparing a new edition of my translation of Galileo’s Sidereus Nuncius. 

This year I will finish a book on Christiaan Huygens and the telescope.

Selected Publications: 

• The Invention of the Telescope.  American Philosophical Society, Transactions, 67 (1977), no 4.  Reprinted with a new introduction, Transactions, 98, part 4 (2008)
• Measuring the Universe: Cosmic Dimensions from Aristarchus to Halley.  Chicago: University of Chicago Press, 1985.
• Sidereus Nuncius or The Sidereal Messenger (Galileo Galilei).  Translated with introduction, conclusion and notes.  Chicago: University of Chicago Press, 1989, new editions, 2014.
• The History of Science in the Netherlands. (Leiden: E. J. Brill, 1999), co-edited with L. C. Palm and K. van Berkel