The STereo Imaging Channel (STC) is one of the three channels of the SIMBIO-SYS instrument on board the BepiColombo ESA spacecraft. The design of the camera consists in a double wide-angle camera with two sub-channels looking at ±20° with respect to the nadir direction. Each sub-channel can acquire three quasi-contiguous areas of the Mercury surface in different colours determined by the filters mounted on the detector. The filters are divided in two categories: 4 broad band filters (20 nm of bandwidth and centred at 420, 550, 750 and 920 nm respectively) necessary to the chemical analysis of the Hermean surface; 2 panchromatic (PAN) filters with 200 nm of bandwidth and centred at 600 nm, designed for the stereo acquisition. The nominal Field of View (FoV) of each sub-channel is 5:38°x4:8°. The in-flight stellar calibration will be performed during the nominal mission using stellar fields images. To effectively plan this calibration activity, two analyses have been performed: the first one consists in simulating the observation of stars having different apparent magnitude to derive the best integration time needed to reach a specific Signal to Noise Ratio. Considering the characteristics of the STC camera and of its CMOS detector, the threshold magnitude needed for a star to be detectable will also be determined. The second part consists in selecting the stellar fields from the ESA GAIA archive and Tycho stellar catalogue that contain a pre-defined minimum number of stars required to perform the in-flight geometrical calibration. This selection have been performed taking into account stars brighter than the threshold defined in the first part.
Setting the parameters for the stellar calibration of the SIMBIO-SYS STC camera on-board the ESA BepiColombo mission
Naletto G.;
2020
Abstract
The STereo Imaging Channel (STC) is one of the three channels of the SIMBIO-SYS instrument on board the BepiColombo ESA spacecraft. The design of the camera consists in a double wide-angle camera with two sub-channels looking at ±20° with respect to the nadir direction. Each sub-channel can acquire three quasi-contiguous areas of the Mercury surface in different colours determined by the filters mounted on the detector. The filters are divided in two categories: 4 broad band filters (20 nm of bandwidth and centred at 420, 550, 750 and 920 nm respectively) necessary to the chemical analysis of the Hermean surface; 2 panchromatic (PAN) filters with 200 nm of bandwidth and centred at 600 nm, designed for the stereo acquisition. The nominal Field of View (FoV) of each sub-channel is 5:38°x4:8°. The in-flight stellar calibration will be performed during the nominal mission using stellar fields images. To effectively plan this calibration activity, two analyses have been performed: the first one consists in simulating the observation of stars having different apparent magnitude to derive the best integration time needed to reach a specific Signal to Noise Ratio. Considering the characteristics of the STC camera and of its CMOS detector, the threshold magnitude needed for a star to be detectable will also be determined. The second part consists in selecting the stellar fields from the ESA GAIA archive and Tycho stellar catalogue that contain a pre-defined minimum number of stars required to perform the in-flight geometrical calibration. This selection have been performed taking into account stars brighter than the threshold defined in the first part.Pubblicazioni consigliate
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