| Abstract: | The results from hourly measurements of the magnetic field strengths of several main spots in three selected spot groups within the years 1968/69 are given in graphs. The values of the field strength used in the graphs are mean values out of three spectrograms taken immediately one after another. The mean error of a mean value is ±85 Gauss. Besides a general tendency in the daily course of the field strength the graphs are showing rapid variations up to 500 Gauss within a few hours. In contrast to these variations which are probably real, the frequent short time variations indicated cannot be regarded as certain. In addition to the observations of the field strength the development of the spot groups is described, and informations on the flare-activity are given. |
