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 telescope, a millimeter-wave, balloon-borne experiment that measures anisotropy in the cosmic microwave background radiation on 0.degrees 5 angular scales. The gondola is capable of maintaining orientation to 2' rms and determining absolute pointing to 2.'5 accuracy 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.