Physics of auroral phenomena : proceedings of the 36th Annual seminar, Apatity, 26 February – 01 March, 2013 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2013. - 215 с. : ил., табл.

В. V. Kozelov et al. Taking the F 557.7 value as a referenced point, we can write: K W = I ^ l Ks577 = “ ^^■^557.7 exP(- ^557.75) (9) This spectral dependence of the calibration factor is shown in Fig.4 for several camera gain levels. Directly calculated values for >.=557.7 nm, >.=427.0 nm and л=630.0 nm and gain level g=680 are shown by symbols. While the curves normalized by value for A.=557.7 nm, the directly calculated values for Л=427.0 nm and A.=630.0 nm are also well correspond to the theoretical curve, that is additional validation of the result. voltage, V Fig. 3 The current-voltage characteristics of the LED low-light source SID-105 for 3 settings. The crosses are measured points; the lines are the interpolations by equations (4)-(6). 4. Conclusions Two CCD cameras used for auroral observations {Kozelov et al., 2012) have been calibrated by LED low- light source ‘PGI-Chemouss-38AM’. The calibration factor as a function of the wavelength and the camera gain was deduced. Previously the light source PGI- Chernouss-38AM (SID 105) was absolutely calibrated during the intercalibrational workshop of optical low light sources {Brandstrom et al., 2012), and it was found some issues motivated additional studies of the light source. The current-voltage and emission intensity characteristics of the light source have been measured. It has been found recommendation for the light source users. Norway through the project named: Norwegian and Russian Upper Atmosphere Co-operation on Svalbard part 2 #196173 / S30 (NORUSCA2). Table 3. Deduced calibration constants for cameras G-l and G-2 in three wavelengths._____________________ G -l G-2 ^557.7 [R S CTS"‘] 1.3xl0 4 ± 2 0 % 1.4xl0 4 ± 2 0 % /W R s C T S - '] 2.5x10s ± 2 0 % 2 . 8 x l 0 5 ± 2 0 % F 427 .o[RsCTS-'] 9 x l0 3* ±30% 9 x l0 3 * ±30% * increased by factor 1 . 6 . и о '• : 1О2 . . . . . .............. ■ _______ _ . 3 5 0 4 0 0 4 5 0 5 0 0 5 5 0 6 0 0 650 w a v e l e n g t h [ n m ] Fig.4 The G-l and G-2 cameras calibration factor K\. Black lines are the calibration factor for several gain levels. Symbols with error bars are values deduced from calibration by low light source SID 105. References Brandstrom B.U.E., et al.: Results from the intercalibration o f optical low light calibration sources 2011, Geosci. Instrum. Method. Data Syst., 1, 43-51, 2 0 1 2 , http://www.geosci-instrum-method-data- syst.net/ 1/43/2012/doi:10.5194/gi-1-43-2012. Kozelov B.V., et al.: Multi-scale auroral observations in Apatity: winter 2010-2011, Geosci. Instrum. Method. Data Syst., 1, 1-6, 2012, www.geosci-instrum- method-data-syst.net/1/1/2012/doi: 10.5194/gi-1-1- 2012 . AVT Guppy.Technical Manual V7.I.0. Allied Vision Technologies GmbH, Germany. 2009. A cknow ledgem en ts. This work was partly supported by Program 22 o f the Presidium of Russian Academy of Sciences, grant 11-02-00397 of Russian Foundation for Basic Researches, and by The Research Council of 154