Longitudinal asymmetries of the coronal line intensities

The analysis of the daily measurements of the coronal green line intensity which have been collected by the Pic-du-Midi Observatory during the period 1944-1974 has directed to some very interesting results. The main finding of this analysis is a permanent longitudinal asymmetry of the green line intensity which has been determined all along the data record. In our effort to make this asymmetry certain we have examined E-W intensity differences very close to the solar equator where the rotation rate for coronal features is equal to 25.35 days on the average. When we examine these data every 25 days, namely data which almost correspond to the same points of the solar disk, we confirm the above mentioned longitudinal asymmetry.