Toward High-Precision Astrometry with CSST Using Multi-Gaussian Fitting of PSF
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arXiv
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| Autori principali: | , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866915446350938112 |
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| author | Nie, Jialu Wei, Peng Cao, Zihuang Yan, Yibo Liu, Chao Tian, Hao Zhang, Xin Tian, Haijun |
| author_facet | Nie, Jialu Wei, Peng Cao, Zihuang Yan, Yibo Liu, Chao Tian, Hao Zhang, Xin Tian, Haijun |
| contents | The Chinese Space Station Survey Telescope (CSST) presents significant potential for high-precision astrometry. In this study, we show that the point spread function (PSF) modeled by the discrete PSF with Multi-Gaussian function can effectively enhance the astrometric accuracy. We determine that the PSF profile can be accurately modeled by three Gaussians, which takes advantage of reduced computational complexity in PSF convolution. In sparse star fields, the lowest centering accuracy we obtain after aberration correction can be below 1 mas. We find that the proper motion errors remain below 1.0 mas/yr for point sources with five observations and approximately 0.8 mas/yr for seven observations with a time baseline of around 3.5 years. We finally demonstrate that the precision of our position measurements for stars fainter than 21 mag in the simulated CSST crowded field is better than the results from both SExtractor and DOLPHOT. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_10329 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Toward High-Precision Astrometry with CSST Using Multi-Gaussian Fitting of PSF Nie, Jialu Wei, Peng Cao, Zihuang Yan, Yibo Liu, Chao Tian, Hao Zhang, Xin Tian, Haijun Instrumentation and Methods for Astrophysics Astrophysics of Galaxies The Chinese Space Station Survey Telescope (CSST) presents significant potential for high-precision astrometry. In this study, we show that the point spread function (PSF) modeled by the discrete PSF with Multi-Gaussian function can effectively enhance the astrometric accuracy. We determine that the PSF profile can be accurately modeled by three Gaussians, which takes advantage of reduced computational complexity in PSF convolution. In sparse star fields, the lowest centering accuracy we obtain after aberration correction can be below 1 mas. We find that the proper motion errors remain below 1.0 mas/yr for point sources with five observations and approximately 0.8 mas/yr for seven observations with a time baseline of around 3.5 years. We finally demonstrate that the precision of our position measurements for stars fainter than 21 mag in the simulated CSST crowded field is better than the results from both SExtractor and DOLPHOT. |
| title | Toward High-Precision Astrometry with CSST Using Multi-Gaussian Fitting of PSF |
| topic | Instrumentation and Methods for Astrophysics Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2508.10329 |