夜间整层大气透过率测量技术研究

Study on measurement technology of total atmospheric transmittance at night

分析了夜间利用恒星测量整层大气透过率的原理,研制了用于夜间整层大气透过率测量的设备,该设备能够对高度角大于15°的任意天区内的0~5等恒星在400~750 nm分波段弱辐射大气透过率测量,测量带宽为30 nm。采用自动控制CCD曝光时间的方法获取分波段恒星的弱辐射信号,利用图像反馈模式纠正望远镜追星的误差,实现无人值守自动连续整夜观测。设备定标采用Langleyplot定标方法与多目标星定标方法相结合。测量结果分别与CART和Modtran理论计算值进行了比较,比较结果证明了测量方法的可行性和设备的可靠性。

The principle of measuring nighttime total atmospheric transmittance was analyzed and the equipment was developed to measure weak radiation atmospheric transmittance within any sky zone of elevation angle greater than 15° from level 0 to level 5 magnitude stars during the spectral band of 400 -750 nm, and the bandwidth of measurement was 30 nm. The method of automatically controlling CCD exposure time was used to obtain a sub-band weak radiation signal of stars, using image feedback mode to correct errors in the telescope searching-stars, which realized automatic unattended continuous observation all night. The equipment calibration adopted the combination of Langley - plot calibration method and multi-objective star calibration method. The measurement results were compared with the simulated values of CART and Modtran, which verified the feasibility of the measurement method and the reliability of the equipment.