A search for anisotropy in the cosmic microwave background at 90 GHz

A ground based search for degree-scale anisotropy in the cosmic microwave background radiation at 90 GHz was performed from the South Pole in January 1993, using a 2 x 2 array of single-mode bolometric detectors on a 0.75 m telescope. Significant sky fluctuations were detected, which give 95% confidence intervals of root C-0 = 3.1 +/- (2.5)(0.8) and 3.8 +/- (2.9)(1.2) x 10(-5) for a model with a Gaussian correlation function with a width of 1 degrees, for the left- and right-hand sides of the array respectively. In this paper we concentrate on the observing strategy and analysis of data from that search.