Comments to the paper i lisac, "overview of scientific activites in geomagnetism and aeronomy in Croatia"

Abstract

The auroral data from Croatia are of great interest as examples from middle latitude stations. The descriptions given by Lisac are not new; in general the development of auroras is well described from many observations in middle latitudes, e.g. from Germany (Schroder 1964). The auroral phenomenon of November 11, 1991 is also well-documented from other European parts. It is of more interest to have details on the earliest observations from Croatia after the so-called Maunder-Minimum (1645–1715). The indicated years in Lisac’s report are connected with times of solar maxima (1738.7 and 1750.3). Many auroras have been reported in the years 1737 and 1750 by European observers. During or near the solar minima (1734.0 and 1745.0) auroras were seldom observed in Central Europe, and consequently very seldom in the latitudes of Croatia and other places. It is known that after 1710 the interest in auroras increased in Europe. A key event was the great aurora of March 17, 1716 (see Schroder 2001). Following this event a general discussion started on the physical nature of these phenomena, and C Wolff (see Schroder 2001) and others pointed out their natural origin. Since this time auroras have been mostly well-documented from middle latitudes and interpreted as atmospheric phenomena.