The polarization of the inner solar corona at the eclipse of 10 July 1972

Photographs of the corona in the continuum spectrum (580-700 nm) have been obtained with a doublet camera (F=4 m) through rotating sector polarizers with the vibrational directions oriented radially and tangentially to the solar limb. Isophotes of the total emission and its polarized component, as well as diagrams giving the degree of polarization for the (K + F)-corona and the electron corona proper (Psub(K)), have been plotted up to the distance of 1 solar radius from the limb. In some inner regions the polarization Psub(K) exceeds the highest value possible for Thomson scattering under the given conditions. The reality of this anomaly is dubious; systematic photometrical errors may account for it. Three-dimensional forms of 15 different coronal rays have been ascertained by comparing the course of polarization along the rays to the family of Baumach curves. The rays are found to deflect substantially from the radial directions out of the plane of the sky. Mean values of the coronal brightness and polarization versus the distance from the Sun have been determined. Contrary to well-known models (Van de Hulst) the mean polarization of the electron corona (Psub(K)) decreases with distance after reaching the maximum (approximately 50%) at (1.4-1.6) solar radii from the Sun's centre. This decrease can be explained by deflection of the streamers from radial directions. (Auth.)