Abstract: According to photometric measurement, the orbit performance of space targets is judged and the identification catalog about space targets is carried out. The applications of optoelectronic telescopes in the domain of space target identification are summarized and discussed. A method for detecting dark space targets is tested, which is called the Hough transform. The factors which affect the limiting-magnitude of optoelectronic telescopes are analyzed by simulation and calculations. Based on the general signal-to-noise ratio formulation for the CCD detector, the theoretical results of limiting-magnitude of optoelectronic telescopes are derived and calculated, which are demonstrated and validated with the method of star-map comparisons. Experiment results show star-map comparison is a reliable method for detecting star magnitude.