BAFFLING AND SHIELDING SYSTEM FOR A MILLIMETER-WAVE BALLOONBORNE TELESCOPE

We describe a balloon borne telescope devoted to millimeter observatio ns of diffuse sky radiation and optimized with a custom set of baffles and shields. The basic idea of the shield design is to shape the surf aces as roof mirrors to redirect the stray radiation in the opposite d irection of incidence. The baffles are used to stop radiation close to the field of view. In this way we are able to avoid most of the unwan ted radiation. We successfully operated this telescope (ARGO) during t wo flights, in 1989 and 1993, while detecting the faint structures of the cosmic microwave background at degree scale. (C) 1998 Optical Soci ety of America.