World first complex optical instrumental observations of aurora in the Arctic in 1899−1900

Abstract

Abstract. This report presents data and analysis of visual, photographic and auroral spectral data, obtained by the Russian astronomer J. Sykora from the Russian-Swedish expedition to Spitsbergen during the 1899-1900 winter season, which are historically significant for auroral studies. These data seem to be the first instrumental observations of auroral spectra in the Arctic and some of the emissions discovered have world priority. The second known photos in the world of aurora from the Arctic and undoubtedly the first ones for geomagnetic latitudes of about 75 • in the Spitsbergen Archipelago were obtained. The results of the expedition are discussed from a modern point of view and compared with our knowledge of the 21st century. A description of the equipment and methods that were used by Russian astronomers is presented. Both photographic and spectral devices using registration by photographic plates were used, along with special methods of their development and enhancement. Some statistical analysis was done on the basis of the expedition reports and diaries. This analysis shows that by using Sykora's data it was possible to discover the auroral oval or instantaneous auroral distribution over the polar region. Analysis of photographic samples and sketches of the aurora demonstrate typical auroral form outlines as they are described today. Spectral plates exposed for several hours to auroral lights revealed not only the main auroral emissions, which were well-known at that time, but several other unidentified weak emissions, which were rediscovered and interpreted years later.

Comparison and significance of auroral studies during the Swedish and Russian bilateral expedition to Spitsbergen in 1899–1900

“…The angle measurements were based on fixed markers in surrounding mountains and sometimes the positions of stars. Details are described in Chernouss et al (2005). It is of interest to point out that the weather conditions for observations at Treurenberg Bay and Konstantinovka are strongly different because of Spitsbergen relief and seaside coast, and simultaneous observations were not so often possible.…”

“…A description of the history of auroral photography, presentation of instruments, and some auroral photos obtained by Sykora in 1899 in Konstantinovka was given in Chernouss et al (2005). During the same period, photos of aurora were also obtained by Westman.…”

“…Sketches of aurora drawn by Sykora (Chernouss et al, 2005) give additional information about the position of the aurora, since in these figures relief and mountain features were included as markers of azimuth and elevation angles. They are also very useful to understand the observed morphology of aurora.…”

“…Westman used a visual microscopy method, which permitted him to see weak emissions on the plate, but did not permit him to prepare well documented evidence of that. Sykora did special processing of primary negatives by preparation of high contrast dianegatives, which gave enhanced spectral images ready for printing (Sykora, 1901a,b;Chernouss et al, 2005).…”

“…The main reason for writing this paper was that the Russian and Swedish auroral measurements were never discussed together as a joint work. A reanalysis of Russian data has been reported by Chernouss et al (2005).…”