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arXiv · 1910.04307

Multi-star Turbulence Monitor: A new technique to measure optical turbulence profiles

Paul Hickson·Bin Ma·Zhaohui Shang·Suijian Xue
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Abstract

The strength and vertical distribution of atmospheric turbulence is a key factor determining the performance of optical and infrared telescopes, with and without adaptive optics. Yet, this remains challenging to measure. We describe a new technique using a sequence of short-exposure images of a star field, obtained with a small telescope. Differential motion between all pairs of star images is used to compute the structure functions of longitudinal and transverse wavefront tilt for a range of angular separations. These are compared with theoretical predictions of simple turbulence models by means of a Markov-Chain Monte-Carlo optimization. The method is able to estimate the turbulence profile in the lower atmosphere, the total and free-atmosphere seeing, and the outer scale. We present results of Monte-Carlo simulations used to verify the technique, and show some examples using data from the second AST3 telescope at Dome A in Antarctica.

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Paul Hickson, Bin Ma, Zhaohui Shang, Suijian Xue. 2019-10-10. Multi-star Turbulence Monitor: A new technique to measure optical turbulence profiles. https://doi.org/10.1093/mnras%2Fstz568

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