Occultations of the Crab Nebula by the Solar Corona in June 1957 and 1958

Abstract

A description is given of some observations of the occultations of the Crab nebula by the solar corona in June 1957 and 1958, obtained with pencil-beam, fan-beam, and interferometer-type instruments. It is shown that the distribution of 85· 5 Mc/s radiation on days when the angular separation is less than 10 solar radii is not consistent with a symmetrical scattering process. Better agreement is obtained by postulating the existence of scattering and regular refraction of comparable magnitude. Certain unexplained features of the pencil-beam distributions indicate that large-scale electron irregularities may be important in the scattering and refraction process. Additional evidence is presented for very short-term changes in the transmission properties of the corona.