A rooftop radio observatory: An undergraduate telescope system at the University of California at Berkeley

We describe the 1- to 2-GHz radio telescope built by undergraduates with faculty guidance at the University of California at Berkeley. The telescope is optimized to observe the 1420-MHz (21-cm) emission line of neutral atomic hydrogen and is used in the recently created advanced undergraduate radio astronomy laboratory course, as well as in part of a graduate course on astronomical observation. We discuss the design of the telescope and the structure of the course and also present astronomical observations made with the telescope. (C) 1998 American Association of Physics Teachers.