VERTECS: pre-flight performance of the optical multi-band camera module

VERTECS is a CubeSat designed to study the Extragalactic Background Light (EBL). We conducted pre-flight performance tests of the optical multi-band camera module installed in VERTECS. The camera module uses a commercially available CMOS sensor controlled by a custom-made image capture board. The sensor temperature is maintained below 0°C by the radiator during the observation in orbit. Through the tests, the detectability of the EBL was assessed while considering radiation effects. The detector noise evaluation showed that the detector noise was dominated by readout noise below 0°C, and the shot noise due to zodiacal light dominates over the detector noise in most observation sky regions. By comparing the noise during the observation with the signal electron count by the EBL estimated through the spectral responsivity evaluation, it was demonstrated that VERTECS can detect the EBL with the sufficient signal-to-noise ratio.