First observations from a CCD all-sky spectrograph at Barentsburg

Abstract. A digital CCD all-sky spectrograph was made by the Polar Geophysical Institute (PGI) to support IPY activity in auroral research. The device was tested at the Barents-burg observatory of PGI during the winter season of 2005– 2006. The spectrograph is based on a cooled CCD and a transmission grating. The main features of this spectrograph are: a wide field of view (∼180◦), a wide spectral range (380–740 nm), a spectral resolution of 0.6 nm, a background level of about 100 R at 1-min exposure time. Several thou-sand spectra of nightglow and aurora were recorded during the observation season. It was possible to register both the strong auroral emissions, as well as weak ones. Spectra of aurora, including nitrogen and oxygen molecular and atomic emissions, as well as OH emissions of the nightglow are shown. A comparison has been conducted of auroral spec-tra obtained by the film all-sky spectral camera C-180-S at Spitsbergen during IGY, with spectra obtained at Barents-burg during the last winter season. The relationship between the red (630.0 nm) and green (557.7 nm) auroral emissions shows that the green emission is dominant near the minimum of the solar cycle activity (2005–2006). The opposite situa-tion is observed during 1958–1959, with a maximum solar cycle activity