A Balloon-borne Millimeter-Wave Telescope for Cosmic Microwave Background Anisotropy Measurements

We report on the characteristics and design details of the Medium Scale Anisotropy Measurement (MSAM), a millimeter-wave, balloon-borne telescope that has been used to observe anisotropy in the Cosmic Microwave Background Radiation (CMBR) on 0\fdg5 angular scales. The gondola is capable of determining and maintaining absolute orientation to a few arcminutes during a one-night flight. Emphasis is placed on the optical and pointing performance as well as the weight and power budgets. We also discuss the total balloon/gondola mechanical system. The pendulation from this system is a ubiquitous perturbation on the pointing system. A detailed understanding in these areas is needed for developing the next generation of balloon-borne instruments.