Solar cycle variations of coronal structures

Using eclipse pictures of the solar corona, properly scaled drawings have been prepared to constitute a short atlas of coronal structures. These drawings have been used to extract 2 parameters which are further considered with respect to the sunspot number and the sunspot cycle: the extension of polar regions free of coronal streamers and the ''average'' radial deviation of large streamers. The flattening index deduced from the photometric analysis of a larger number of eclipse pictures is also considered. The out of phase behaviour of several coronal parameters is confirmed. The results are discussed in the light of the analysis of the green line activity as observed during 30 years at the Pic du Midi Observatory. The N-S asymmetric behaviour of the activity in different solar hemispheres and the occurrence of powerful secondary maximum of coronal activity are discussed