用CCD照相多幅叠加处理检测弱星的试验

本文利用CCD动态范围大且便于数值处理的优点,观测月晕中(强背景上)的弱源。在背景尚未使CCD片子饱和时,即停止露光,存入计算机,多次露光,然后在计算机内多幅叠加,减去背景,显出弱源。通过观测试验和定量估算,结果表明,曝光重叠法,用10幅图叠加时能提高信噪比2.65倍。实测与理想情况符合较好。

Test of the Detection of Weak Stars by Means of the Overlap of Their Several Images Obtained with A CCD

A method for observing the weak sources hidden in the strong background is presented in this paper by making use of the advantages of the wider dynamic range and convenient data processing of a CCD During the observation, before the background glow makes the plate of the CCD be saturated stop the exposure and store the image in the computer system. The plate exposures to the background glow several times according to the above-mentioned method and then the images are overlapped in the computer. The weak sources appear after the background elimination. From the observational test and quantitative estimate, the results show that the signal noise ratio can increase by 265% when 10 images are overlapped and the observed results are in accordance with the perfect ones well.