High-precision photometry with a scientific CMOS camera: I lab testing of the Marana camera

Abstract

Scientific complementary metal-oxide semiconductor (CMOS) cameras are becoming increasingly prevalent in modernobservational astronomy. We assess the ability of CMOS image sensors technology to perform high-precision photometrywith a detailed laboratory characterization of the Marana 4.2BV-11 CMOS camera. We characterize the camera in the fastestframe rate (FFR) and high dynamic range (HDR) modes. Our evaluation includes read noise, dark current, photo response anddark signal non-uniformities, quantum efficiency, and window transmittance. The read noise is found to be 1.577 e− for the FFRmode. For the HDR mode the read noise floor is measured to be 1.571 e− for signal levels below approximately 1800 e−. Thebias level shows dark signal non-uniformities with values of 0.318 e− and 0.232 e− for FFR and HDR mode, respectively. Pixelwell capacity reached 2366 e−pix−1 for the FFR mode and 69026 e−pix−1 with a dynamic range of 93 dB for the HDR mode.The camera demonstrates good linearity, yielding linearity errors of 0.099 per cent for FFR mode and 0.122 per cent for HDRmode. The uniformity across the image arrays show a photo response non-uniformity of 0.294 per cent for the FFR mode and0.131 per cent for the HDR mode. The dark current displays a noticeable glow pattern, resulting in mean dark current levels of1.674 ± 0.011 e− pix−1 s−1 for the FFR mode and 1.617 ± 0.008 e−pix−1 s−1 for the HDR mode at a constant temperature of−25 ◦C. We measured the quantum efficiency across the visible spectrum, with a peak of of >95 per cent at 560 nm. Our testsindicate that the Marana CMOS camera is potentially capable of performing precise photometry.