My office is 4550 Sterling Hall — just along from the big coffee area on the 4th floor of the 1959 wing of the building.
I can be contacted at the following address:
Department of Astronomy
University of Wisconsin-Madison
5534 Sterling Hall
475 N. Charter Street
Madison WI 53706-1582
I can also be reached via email at townsend AT astro DOT wisc DOT edu.