Abstract: It conducts a comparative study of photometry on the bright stars and dark stars, using ePSF(effective-Point-Spread-Function) and Gaussian function. The stars in the 16 CCD images observed by National Astronomical 1 m telescope were divided into two types of stars, bright stars and dark stars according to the average luminosity, and each of the ePSF was calculated and used to measure the stars. The results reveal that the precision rate is higher if the ePSF of bright stars is used to measure bright stars, and the precision rate is higher if the Gaussfitting is used to measure dark stars. The ePSF has obvious advantages to measure the precision of bright stars while the Gaussfitting is better for dark stars, which shows that the morphological structure of the dark star is closer to Gaussian distribution.

Key words: effective-point-spread-function（ePSF）; Gauss-fitting; photometry; precision