The excitation of the coronal line 5303A

The relation between the intensities of the line 5303 A and that of the nearby continuum has been investigated at the solar eclipse of March 7, 1970. As this relation depends on the local structure of the corona, spectrograms have been taken at 16 different position angles. For the present investigation, 4 spectrograms have been selected that show the line 5303A up to r=2. For distances r>1.8 the ratio of line-to continuum-intensity, Q, becomes constant. This is the region where the excitation by radiation dominates. Towards smaller distances Q increases as the excitation by collisions becomes more important. At r=1.3 the contributions from both mechanisms are equal. For r<1.3 Q increases stronger than expected for an isothermal and homogeneous model. In the innermost corona the observed values are twice as high as the theoretical ones. This difference can be accounted for by inhomogeneities of the corona. (Auth.)