中文摘要：

详细介绍了利用孔径测光方法得到CCD图像中恒星仪器星等的全过程，以及使用自己设计的程序对云南天文台1m望远镜观测的CCD图像进行实际测量的实验。测量结果表明：对亮星（约10mag）的内部测量精度能达到0．003mag，而对暗星（约17mag）达到0．2mag。同时，对相关问题进行深入讨论，总结了一些实验所得的经验，并与测光软件IRAF进行了内部精度的比较。

英文摘要：

This paper describes the details of the procedure of deriving instrumental stellar magnitudes from a CCD image using aperture photometry. We conducted experiments of the procedure based on CCD images obtained with the 1 m telescope of the Yunnan Observatory. The results reveal that the internal precisions are 0. 003mag and 0.2mag for a bright star（ - 10mag） and a faint star（ - 17mag） , respectively. In addition, we discuss related issues and some experiences from the experiments. The comparison to the results from the photometric software IRAF is presented as well.