月基望远镜探测能力的地面标定

摘要

采用模拟试验在地面测试了月基望远镜(LOT)的星等探测信噪比及弥散斑能量集中度,用以验证望远镜的探测能力.与传统的通过分析CCD各项参数对噪声的影响来获得信噪比的方法不同,本文提出的方法客观、直接地通过图像信息来计算星点目标信噪比,其目标信噪比测试不确定度可优于8％.在测试弥散斑能量集中度时,通过质心算法求其弥散斑能量中心,进而提出了一种星点弥散斑高斯拟合方法来拟合弥散斑能量分布曲线.这种高斯拟合方法可使弥散斑能量集中度的测试精度提高10％.最后,通过试验测试了LOT相机星等探测信噪比及弥散斑能量集中度,验证了LOT相机+15 Mv的探测能力.%The Signal-to-noise Ratio (SNR) of star-level detection and the energy concentration of a dispersed spot for an lunar-based Optical Telescope(LOT) are tested by using a simulation experiment on ground to verify its detection capability. Unlike the conventional methods that use the effect of CCD hardware parameters on the noise to test the SNR,the new test method directly uses the observation information to compute the SNRs of star targets and the tested uncertainty of object SNRs can be better than 8%. In the test of energy concentration, the centroid algorithm is used to computer the center of the dispersed spot and a Gaussian fitting method is proposed to fit the curve of the energy distribution. The Gaussian fitting method can significantly improve the detection precision of the energy concentration for the dispersed spot, and the testing precision has been improved by 10%. Finally, the detection capability of +15Mv of the LOT is verified by an experiment on the SNR of star level detection and the energy concentration of dispersed spot for the LOT.