Precise Estimation of Source Intensity for Wide-field Telescopes with PSF Modeling

Abstract

Abstract Wide-field small aperture optical telescopes are widely used in large-scale surveys currently and they have made great contributions in a number of astronomical applications. However, specific challenges arise owing to the defects caused by the optical system, and the image quality and reduction precision are negatively affected. An innovative method is proposed to address these challenges and achieve a high-precision source intensity estimation. In implementation, first a dedicated pipeline is developed to investigate the point-spread function (PSF) components from large amounts of images, using principal component analysis. Then the PSF model that reveals the actual characteristics of the optical system is constructed based on the evaluation. Last the equations for centroid and intensity estimation are constructed and the results are obtained. A trial of observations is performed with a wide-field small aperture telescope, and a large number of raw images, as well as simulated images, are acquired to test the efficiency of our method. The intensity measurement is performed with our method and other common algorithms, including the modified moment, Gaussian fitting, and SExtractor. Based on the comparison it is demonstrated that our proposed method outperforms the others. The results indicate that our method explores the limitations of such a system and additional gains can be achieved in wider applications.