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To determine the precise positions of stars in CCD frames, various centeringalgorithms have been proposed for astrometry. The effective point spreadfunction (ePSF) and the Gaussian centering algorithms are two representativecentering algorithms. This paper compares in detail and investigates these twocentering algorithms in performing data reduction. Specifically, synthetic starimages in different conditions (i.e. profiles, fluxes, backgrounds and fullwidth at half maximums) are generated and processed. We find that thedifference in precision between the two algorithms is related to the profilesof the star images. Therefore, the precision comparison results using an idealGaussian-profile star image cannot be extended to other more specificexperimental scenarios. Based on the simulation results, the most appropriatealgorithm can be selected according to the image characteristics ofobservations, and the loss of precision of other algorithms can be estimated.The conclusions are verified using observations captured by the 1-m and 2.4-mtelescopes at Yunnan Observatory.

Investigation and Application of Fitting Models for Centering Algorithms in Astrometry