钠激光导星星等计算方法研究

首先简要介绍一套完整的激光导星实验系统,并获得了大量的导星图像数据.在此基础上,采用与已知自然星实时对比的方法计算得到钠激光导星V波段星等,使用了灰度值图像和光子数图像数据,并将光子数图像转换为光子返回数对已知自然星等的理论值进行验证.重点分析了窄带滤光片等因素对计算过程的影响.最后对计算结果精度等作了简单的讨论.初步计算结果表明,在长春的城市天光背景下,通过平均功率5.2W、线宽4–5pm的589nm激光器在夏季激发的导星亮度约为14.05等.

Research on the calculation method of sodium laser guide star magnitude

This paper briefly introduces a complete sodium laser guide star experimental system first. A lot of guide star images have been obtained. A method of real time comparison with a known natural star is adopted to calculate the V-band magnitude of the guide star. Grey value image data and photon-count image data are both used in the calculation. Moreover, the photon-count image data is converted to return flux to verify the theoretical magnitude of the known natural star. The influence of a narrow band optical filter on the calculating process is analyzed and emphasized. Finally, a simple discussion is made on the accuracy of the calculation result. The preliminary result shows that, under the condition of sky background light of Changchun city, the brightness of the guide star excited in summer by a 589 nm laser which has an average power of 5.2 W and a bandwidth of 4-5 pm is about 14.05My.