基于EMCCD相机的全天时大气相干长度测量系统

摘要

根据差分像运动原理研制出一款以EMCCD相机为探测器的全天时大气相干长度观星测量系统.经过对天空背景光光谱分布与EMCCD光谱响应特性的分析,选择中心波长为700 nm的光谱滤光片,可有效地抑制背景光入射.介绍了系统主要噪声组成,通过计算得到了系统白天极限探测星等约为7.35.在野外开展了以小熊星座所属多颗不同星等恒星为目标的日间观星实验,结果表明测量系统对星等为3恒星具有较好的日间探测能力.通过全天24h对大气相干长度的连续测量,得到了长春地区整层大气湍流强度变化特征曲线.%According to the principle of differential image motion,the full-time measuring system of atmospheric coherence length based on EMCCD camera was developed for observing stars.By analyzing the spectral distribution of sky background and the spectral response characteristics of EMCCD,spectral filter with central wavelength of 700nm was selected to suppress the incidence of sky background light.The main noise of measuring system is introduced,and the calculated limiting star magnitude is 7.35 in daytime.Stargazing experiments for some different magnitude stars in the Ursa Minor are carried out in the field.The results show that the measurement system has a good detection capability for star with magnitude 3 in daytime.By continuous measurements of atmospheric coherence length in all-day time,atmospheric turbulence intensity change curve of the whole layer in Changchun was obtained.