Objective  Cameras is a critical component of an optical telescope observation system, and their performance significantly affects the quality and efficiency of astronomical observations. Acquiring camera performance parameters is beneficial in enhancing precision and efficacy of astronomical observations. Numerous worldwide photosensitive chips and camera manufacturers have devised their own performance to test standards based on their experience, to make it difficult to compare products from different manufacturers based on their performance parameters. Although camera performance test can be conducted according to the EMVA1288 standard, and data sheets conforming to EMVA1288 standard can be provided, the standard primarily caters to the machine vision industry cameras, and some of the performance test settings are incompatible with the needs of astronomical optical cameras. Consequently, research on testing technology for astronomical optical cameras is imperative.

  Methods  In astronomical optical observations, the common used cameras are CCD (Fig.1) and CMOS (Fig.2). After analyzing the requirements of astronomical optical observations, the performance test items for astronomical optical cameras are determined to be gain, readout noise, full well capacity, dynamic range, linearity, bias stability, pixel readout noise statistics, photo response non-uniformity (PRNU), and dark current. The photon transfer curve (PTC) method and so on are selected for testing performance items, and definitions and testing methods for each item are explained. In order to verify the feasibility of this set of test items, test methods, test experiments, and data processing methods, the Andor Marana sCMOS and Andor iKon-L 936 CCD cameras (Fig.4) are tested in the laboratory using a testing system set up on a dark optical platform (Fig.5). The gain, readout noise, full well capacity, linearity, bias stability, pixel readout noise statistics, dynamic range, PRNU, and dark current of the sCMOS camera's 12-bit setting and CCD camera's 1 MHz 4× setting are tested, respectively.

  Results and Discussions   A series of performance tests were conducted on the CCD and sCMOS cameras in a laboratory, obtaining performance parameters for the sCMOS 12-bit and the CCD 1 MHz 4× settings (Tab.4): gain, readout noise, full well capacity (Fig.6, Fig.7), linearity (Fig.8, Fig.9), bias stability (Fig.10), pixel readout noise statistics (Fig.11), dynamic range, PRNU, dark current (Fig.12, Fig.13, Fig.14). By comparing the performance test results of the two cameras, the Marana sCMOS 12-bit setting showed approximately half lower readout noise, 17 times higher dark current, 3 magnitude lower dynamic range, and twice as high PRNU compared to the iKon-L936 CCD 1 MHz 4× setting. Both cameras demonstrated high linearity and bias stability. The sCMOS camera exhibited glow, making it unsuitable for long-exposure observations. Through the laboratory tests of the sCMOS and CCD cameras, the performance parameters of cameras were obtained, and the feasibility of the testing items, testing methods, testing experiments, and data processing methods were verified.

  Conclusions  Cameras are essential components of optical telescope observation systems. Acquiring camera performance parameters plays a significant role in formulating astronomical observation plans, adjusting observation strategies, data processing, and diagnosing faults. To enhance the accuracy and efficiency of astronomical optical observations, research on the performance testing of astronomical optical cameras has been conducted. By introducing CCD and CMOS cameras commonly used in astronomical optical observations and analyzing the performance requirements of cameras in astronomical optical observations, camera performance testing items, testing methods, testing experiments, and data processing methods have been established. These testing items include gain, readout noise, full well capacity, dynamic range, linearity, bias stability, pixel readout noise statistics, PRNU, and dark current. 　　To validate the feasibility of this methodology, a detection experiment was constructed based on the defined testing items, testing methods, testing experiments, and data processing methods. A comparative test was conducted using the Andor Marana sCMOS and Andor iKon-L936 CCD cameras to verify the testing items, methods, and data processing methods. Through performance testing experiments on the cameras, the feasibility of the testing items, testing methods, testing experiments, and data processing methods was confirmed. This research enables testing of all settings of a camera, allowing for the acquisition of performance parameters across the entire settings.　　 The proposed method facilitates comparisons between different settings of the same camera or between different cameras, assisting users in selecting cameras or cameras settings that better suit their observational needs, thereby obtaining better observation data. Regular performance testing of cameras can be conducted, and a comprehensive database of performance parameters throughout the camera's lifecycle can be established. This database would facilitate the management of camera health status and diagnosis of faults in the observation system.