Cosmic Microwave Background Anisotropy in the COBE DMR 4-yr Sky Maps

The COBE satellite has provided the only comprehensive multi-frequency full-sky observations of the microwave sky available today. Assessment of the observations requires a detailed likelihood analysis to extract the maximum amount of information present in the noisy data. I present a specific method for estimating the CMB anisotropy power spectrum independent of any assumptions about the underlying cosmology, and then use standard image processing techniques to generate the most revealing corresponding maps of the signal. The consistency of the data at the available frequencies provides strong support to the assertion that we are being provided with our first glimpse of the last scattering surface.