Night-time measurements of astronomical seeing at Dome A in Antarctica
Ma, Bin ; Shang, Zhaohui ; Hu, Yi ; Hu, Keliang ; Wang, Yongjiang ; Yang, Xu ; Ashley, Michael C. B. ; Hickson, Paul ; Jiang, Peng
Seeing—the angular size of stellar images blurred by atmospheric turbulence—is a critical parameter used to assess the quality of astronomical sites at optical/infrared wavelengths. Median values at the best mid-latitude sites are generally in the range of 0.6-0.8 arcseconds1-3. Sites on the Antarctic plateau are characterized by comparatively weak turbulence in the free atmosphere above a strong but thin boundary layer4-6. The median seeing at Dome C is estimated to be 0.23-0.36 arcseconds7-10 above a boundary layer that has a typical height of 30 metres10-12. At Domes A and F, the only previous seeing measurements have been made during daytime13,14. Here we report measurements of night-time seeing at Dome A, using a differential image motion monitor15. Located at a height of just 8 metres, it recorded seeing as low as 0.13 arcseconds, and provided seeing statistics that are comparable to those at a height of 20 metres at Dome C. This indicates that the boundary layer was below 8 metres for 31 per cent of the time, with median seeing of 0.31 arcseconds, consistent with free-atmosphere seeing. The seeing and boundary-layer thickness are found to be strongly correlated with the near-surface temperature gradient. The correlation confirms a median thickness of approximately 14 metres for the boundary layer at Dome A, as found from a sonic radar16. The thinner boundary layer makes it less challenging to locate a telescope above it, thereby giving greater access to the free atmosphere.
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Night-time measurements of astronomical seeing at Dome A in Antarctica
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Ma, Bin et al. 2020. Night-time measurements of astronomical seeing at Dome A in Antarctica. Version 1.0.
doi = {10.12149/101021},
url = {},
author = {Ma, Bin},
title = {Night-time measurements of astronomical seeing at Dome A in Antarctica},
version = {1.0},
publisher = {Nataional Astronomical Data Center of China},
year= {2020}
Version 1.0 (current)
This DOI represents all versions, and will always resolve to the latest one.