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This report presents data and analysis of visual, photographic and auroral\udspectral data, obtained by the Russian astronomer J. Sykora from the\udRussian-Swedish expedition to Spitsbergen during the 1899–1900 winter\udseason, which are historically significant for auroral studies. These data\udseem to be the first instrumental observations of auroral spectra in the\udArctic and some of the emissions discovered have world priority. The second\udknown photos in the world of aurora from the Arctic and undoubtedly the\udfirst ones for geomagnetic latitudes of about 75° in the Spitsbergen\udArchipelago were obtained. The results of the expedition are discussed from\uda modern point of view and compared with our knowledge of the 21st\udcentury. A description of the equipment and methods that were used by\udRussian astronomers is presented. Both photographic and spectral devices\udusing registration by photographic plates were used, along with special\udmethods of their development and enhancement. Some statistical analysis was\uddone on the basis of the expedition reports and diaries. This analysis shows\udthat by using Sykora's data it was possible to discover the auroral oval or\udinstantaneous auroral distribution over the polar region. Analysis of\udphotographic samples and sketches of the aurora demonstrate typical auroral\udform outlines as they are described today. Spectral plates exposed for\udseveral hours to auroral lights revealed not only the main auroral\udemissions, which were well-known at that time, but several other unidentified\udweak emissions, which were rediscovered and interpreted years later.<p>\ud<b>Keywords.</b> History of geophysics (Atmospheric sciences,\udinstruments and techniques

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