基于有效点扩散函数的高精度测光

High-Precision Photometry Based on an Effective Point Spread Function Method

介绍了利用有效点扩散函数拟合方法得到CCD图像中恒星仪器星等的过程。对国家天文台1 m望远镜观测的16幅CCD图像进行实际测量,结果表明:亮星的内部测量平均精度为0.015 mag,最高精度可达0.001 5 mag,而暗星则达到0.043 mag。与Gauss拟合测光方法相比平均精度提高了3倍多,精度标准偏差是0.005,说明该测量方法比较稳定,是一种更优的测光方法。

The paper describes the details of a procedure to obtain instrumental stellar magnitudes from CCD images using an ePSF （effective Point Spread Function） fitting method. We conduct an experiment with CCD images. The average internal error of the method is 0. 015 mag, while the best errors are 0. 001 5 mag for a bright star and 0. 043 mag for a faint star. The precision of the ePSF fitting method is 3 times better than the Gaussian fitting method. The rms error of the ePSF fitting method is 0. 005 mag. The results show that the ePSF fitting method is stable.