By Wilfried Schroeder
On the basis of the analysis of the data of auroral observations at middle latitudes during low solar activity, and modern spectro-photometric research, the feasasibility of their joint use for the estimation of the level of solar activity during periods without instrumental measurements is discussed. In this paper an attempt is undertaken to determine quantitative information of solar activity by comparing the data of visual auroral observations with the modern parameter of their lumininescence.
To appear in Annales Geophysicae 2004