A Robust Geometric Distortion Solution for the Main Survey Camera of CSST
Year: 2026
Type: article
Abstract: The advancement in sensitivity and field of view of next-generation wide-field survey telescopes requires astrometric measurements with high precision, even in the presence of significant geometric distortions. To address this challenge, we develop a Weighted Polynomial Distortion Correction in 2-Phase (WPDC-2P) method. This approach enhances stellar cross matching, incorporates distance-based weighting into the traditional polynomial fitting, and employs a look-up table to absorb the remaining distortion residuals. Validated on simulated data from the Main Survey Camera of the Chinese Space Station Survey Telescope (CSST), incorporating geometric distortions up to approximately 200 pixels, the method achieves astrometric standard deviation ranging from 0.013 to 0.107 pixels (0.03 pixels for the g -1 detector) across all 18 detectors. Under extreme crowding conditions (e.g., globular cluster NGC 2298), the astrometric precision for the g -1 detector reaches 0.05 pixel level within the central region ( r d < 4000), despite a centroiding precision of ∼0.04 pixels. When applied to the Beijing–Arizona Sky Survey data, for which the standard pipeline delivers an astrometric uncertainty of ∼20 mas, our method reduces the positional scatter to σ Δ α = 5.494 mas (0.01 pixels) and σ Δ δ = 9.981 mas (0.02 pixels) using only a weighted third-order polynomial correction. The method has been integrated into the CSST data processing pipeline and is prepared for further refinement using on-orbit calibration data.
Source: The Astronomical Journal
Authors: Yibo 一波 Yan 闫, You 优 Wu 吴, Jundan 俊丹 Nie 聂, Tianmeng 天萌 Zhang 张, Chao 超 Liu 刘, Zhang 章 Ban 班, Zihuang 子皇 Cao 曹, Wei 薇 Du 杜, Yuedong 越东 Fang 方, Yi 义 Hu 胡, Guoliang 国亮 Li 李, Xiaobo 晓波 Li 李, Chenxiaoji 晨晓骥 Ling 凌, Jiaqi 家琪 Lin 林, Dezi 德子 Liu 刘, Yu 煜 Luo 罗, Bin 斌 Ma 马, Xianmin 宪民 Meng 孟, Juanjuan 娟娟 Ren 任, Li 立 Shao 邵, Hao 浩 Tian 田, Chengliang 成亮 Wei 韦, Peng 鹏 Wei 魏, Shoulin 守林 Wei 卫, Yun-Ao 云奥 Xiao 肖, Zhou 洲 Xie 谢, Su 苏 Yao 姚, Yan 彦 Yu 吁, Shengwen 圣文 Zhang 张, Xin 鑫 Zhang 张, Bowei 博伟 Zhao 赵, Zhimin 志民 Zhou 周, Hu 虎 Zou 邹
Institutions: Chinese Academy of Sciences, National Astronomical Observatories, University of Chinese Academy of Sciences, Beijing Normal University, Zhejiang Lab, Changchun Institute of Optics, Fine Mechanics and Physics, Ludwig-Maximilians-Universität München, Purple Mountain Observatory, Sun Yat-sen University, Shanghai Astronomical Observatory, Yunnan University, Hunan Normal University, Kunming University of Science and Technology, Guangzhou University
Language: English
Subfield: Instrumentation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W7146955578