Technology Research and Precision Premium in Relative Photometry Based on CCD Images

The changes of celestial bodies' light with time can reflect their physical properties, and precise photometry technology helps us analyze and explore the changes of light better, which is of great significance to the study of the evolution of celestial bodies. This paper introduces the related photometry tools and technologies and suggests a method of photometry technology and its application by combining MaxIm DL with photutils. Besides, this paper puts forward a fast-matching solution of each star image's photometric data in continuous frames. By analyzing the images of M35 cluster taken by the 1 m optical telescope of Yunnan Observatories, Chinese Academy of Sciences, we find there is a phenomenon of precision premium in relative photometry. Namely, two close stars have better measurement precision in relative photometry, and the significance of this phenomenon is related to the atmosphere mass. According to the phenomenon, this paper proposes some reference methods in high precision relative photometry.