The use of the large MM-wave antenna at Itapetinga in high-sensitivity solar research

Large dishes used in solar radio astronomy are becoming an essential tool for the analysis of low level activity and fine time structures in solar bursts. Some front-end and back-end arrangements have been added to the Itapetinga 13.7-m radome-enclosed antenna to allow for simultaneous 22 GHz and 44 GHz observations; 22 GHz right- and left-handed circular polarization (or two linear orthogonal), with sensitivities of the order of 0.03 s.f.u., and time resolution of 1 ms. Full Sun maps can be obtained every 6 min, and selected active region maps every 3 min. Spatial angular definition of positions of active-region hot spots is close to 10 arc sec. This system is being used in a number of specific investigations, in SMM satellite related research, and in other internationally coordinated works. Examples of results are shown.In memoriam, 1942–1981.