A study of the Northern polar region of the sun using the microwave observations of the total eclipse of March 29, 2006

We report the results of unique observations of the solar eclipse of March 29, 2006 over a wide radio-wavelength range from 1 to 50 cm made with the large RATAN-600 stationary radio telescope during the maximum eclipse phase performed using the method of the source transit across the fixed beam pattern. The multifunctional opportunities of the radio telescope allowed observations to be performed simultaneously in a part of the Northern sector of RATAN-600 and in the Southern-sector plus periscope mode using all the available receiving equipment at the corresponding secondary mirrors. At the time of maximum eclipse phase a narrow 1—3-arcsec wide crescent-shaped band near the North Solar Pole remained visible out of the entire solar disk covered by the Moon. We achieved high flux sensitivity, which allowed us to discover a large polar radio source located above the North Solar Pole and obtain detailed data on its radiation and spatial structure. Moreover, we detected optically thin radiation of the solar corona at the brightness-temperature level of several K or several tens of K. We find this radiation to extend beyond the solar limb out to the heliocentric distances of one solar radius. These data are unique in that they are not contaminated by scattered radiation of the solar radio disk, which usually shows up in ordinary observations. We are the first to obtain a detailed spectrum of the radiation of a high-latitude prominence at many wavelengths with a 1% frequency resolution in the microwave range, which allowed us to estimate its magnetic field at a number of levels in the lower corona.