Observation of radiotelescope RT22 CrAo with the Synthetic Aperture Radar ENVISAT from space

The RT22 CrAO radio telescope antenna has been observed with a C-band Synthetic Aperture Radar (SAR) for the purpose of deriving scattering properties and pointing information. Space-based radars benefit from accurate calibration targets and for the lower frequency bands such targets can be rather large in physical sense in order to derive level information. Active transponders are used. A large reflector antenna has a scattering pattern, which depends on a number of properties and compares with the actual radiation pattern of the antenna (minimum scattering antenna, depending on loading considerations). We have done preliminary investigations by measuring the responses with the SAR on-board ENVISAT.