The plane of polarization of the solar corona during eclipse observations

Analyses of the orientation of the plane of polarization for the solar coro na are presented, based on polarization isophotes of the solar eclipses of June 30, 1973 (Africa), November 3, 1994 (Brazil), and March 9, 1997 (Easte rn Siberia). Deviations of the polarization plane from the radial direction , indeed, exist at distances from the solar limb greater than 0.5 R.. These deviations cannot be explained by the aberration of scattered photons on m oving coronal electrons or by F-corona emission. It is proposed that the de viations are produced by sky polarization (the auroral ring), i.e., by Rayl eigh scattering in the Earth's atmosphere during the eclipse. A model of th e total emission of the corona taking into account the sky background is co nstructed, and the positions of singular points of the polarization tensor with topological index -1/2 are indicated.