Analyses of the Accuracy and Error of the Stellar Photometry with A CCD System——A Method of Astronomical Measurements with CCDs(Ⅰ)

The mathematic model of image pre-processing with a CCD system and the calculating method for measuring the stellar magnitude are presented in this paper. The effects of the sky background, flat correction, noise and bad pixeis on the measurements of the stellar magnitudes are discussed by means of the mathematic model. The analysed results show that the measuring error of the measurements of stellar magnitudes with the No. 1 CCD system of the Yunnan Observatory is generally less than 0.03 magnitudes.