Measurement of a peak in the cosmic microwave background power spectrum from the North American test flight of Boomerang

We describe a measurement of the angular power spectrum of anisotropies in the cosmic microwave background (CMB) at scales of 0 degrees.3 to 5 degrees from the North American test flight of the Boomerang experiment. Boomerang is a balloon-borne telescope with a bolometric receiver designed to map CM B anisotropies on a long-duration balloon flight. During a 6 hr test flight of a prototype system 1997, we mapped more than 200 deg(2) at high Galacti c latitudes in two bands centered at 90 and 150 GHz with a resolution of 26 ' and 16.'5 FWHM, respectively. Analysis of the maps gives a power spectrum with a peak at angular scales of 1 degrees with an amplitude 70 K-mu(CMB).