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Proceedings Paper

A method of real-time analysis for stray light uniformity of optical telescope
Author(s): Taoran Li; Jianfeng Tian; Xue Yang; Ying Wu
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Paper Abstract

The stray light uniformity is one of the important factors affecting the signal-to-noise ratio of the optical astronomical telescope. It will cause regional differences in the background intensity of the detector image, resulting in a decrease of the differential photometry accuracy. The source that affects stray light uniformity is the inconsistency of the brightness of the sky background, which comes from moonlight, bright star, and city lighting pollution. During CCD reduction, the effect of background uniformity cannot be eliminated by dividing the flat field.

Star deletion method is used in real-time stray light analysis. It’s very convenient to achieve a ‘clear’ background image without stars in MATLAB. A contour map of stray light distribution for each object image will be given to demonstrate the background uniformity directly. The stray light uniformity analysis method is implemented by the following steps: 1) CCD reduction, including preprocessing of an object image with bias and flat field; 2) Histogram generation, performing star subtraction automatically based on ADU value and frequency; 3) Background stray light contour map generation, stray light uniformity and other parameters calculations. This method will calculate the uniformity of image surface in real time, provide background intensity distribution, statistical data of the CCD image and suggestion on compare star selection during CCD data processing and improve the photometry accuracy.

Paper Details

Date Published: 19 November 2019
PDF: 6 pages
Proc. SPIE 11185, Optical Design and Testing IX, 111850X (19 November 2019); doi: 10.1117/12.2536715
Show Author Affiliations
Taoran Li, National Astronomical Observatories (China)
Jianfeng Tian, National Astronomical Observatories (China)
Xue Yang, National Astronomical Observatories (China)
Univ. of Chinese Academy of Sciences (China)
Ying Wu, National Astronomical Observatories (China)
Univ. of Chinese Academy of Sciences (China)

Published in SPIE Proceedings Vol. 11185:
Optical Design and Testing IX
Yongtian Wang; Pablo Benítez; Osamu Matoba, Editor(s)

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