It would be useful to know daily the morphology of the outer corona, at distances from the limb of the order of 0.5 to 1 solar radius. Knowledge of the electron corona visible in the continuous spectrum scattered by electrons (K-corona) would be most useful. It would allow one, on the one hand, t... Show moreIt would be useful to know daily the morphology of the outer corona, at distances from the limb of the order of 0.5 to 1 solar radius. Knowledge of the electron corona visible in the continuous spectrum scattered by electrons (K-corona) would be most useful. It would allow one, on the one hand, to check the accuracy of the "model corona" computed by van de Hlst, on the other hand to study the properties of the big coronal streamers: birth, development, position with respect to the active regions of the Sun, variation of number and intensity during the solar cycle, and correlation with geomagnetic activity. NOTE: Original faded, best scan possible Show less