A long term analysis of the green and the red line intensities of the
emitting solar corona as well as the polarization of the white corona,
which have been compiled by the Pic-du-Midi, Kislovodsk, Irkutsk and
Lomnisky Styt observatories, has led to some very interesting results. A
prominent East-West asymmetry is obvious in most of the data while a
very characteristic seasonal variation of this asymmetry with maxima
close to December and minima in July-August is also present. All the
errors involved in coronal optical measurements have been examined in a
previous paper but none of them have been underlined as the possible
cause of the east-west asymmetry. In such a case, the presence of this
asymmetry should not be ignored while the reason for its existence
should be studied, extensively. Two approximations to a possible
explanation of the solar E-W asymmetries have been reported in the
discussion section of this article. (C) 1997 Elsevier Science B.V
