ANISOTROPY IN THE MICROWAVE SKY AT 90 GHZ - RESULTS FROM PYTHON-III

The third year of observations with the Python microwave background ex periment densely samples a 5.5 degrees x 22 degrees region of sky that includes the fields measured during the first 2 years of observations with this instrument. The sky is sampled in two multipole bands cente red at I approximate to 87 and I approximate to 170. These two data se ts are analyzed to place limits on fluctuations in the microwave sky a t 90 GHz. Interpreting the observed fluctuations as anisotropy in the cosmic microwave background, we find flat-band power estimates of delt a T-l = [l(l + 1)C-l/(2 pi)](1/2) = 60(-13)(+15)mu K at l = 87(-38)(+1 8) and delta T-l = 66(-16)(+17) mu K at I = 170(-50)(+69). Combining t he entire 3 year set of Python observations, we find that the angular power spectrum of fluctuations has a spectral index m = 0.16(-.18)(+.2 0) and an amplitude delta T-le = 63(-14)(+15) mu K at l(e) = 139(-34)( +99) for the functional form delta T-l = delta T-le(l/l(e))(m). The st ated uncertainties in the amplitudes and spectral index represent 1 cr confidence intervals in the likelihood added in quadrature with a 20% calibration uncertainty and an estimate of the effects of a +/-0.05 d egrees uncertainty in the measured beamwidths. The limits of I are det ermined from the half-maximum points of the window functions.