The Indian Institute of Astrophysics is developing a Multi-Conjugate Adaptive Optics system for the Kodaikanal Tower Telescope. In this context, we measured the daytime turbulence strength profile at the Kodaikanal Observatory. The first method based on wavefront sensor images, called solar differential image motion monitor+, was used to estimate the higher altitude turbulence up to a height of 5 to 6 km. The second method used balloon-borne temperature sensors to measure the near-Earth turbulence up to 350 m. We also carried out simulations to validate the performance of our system. We report the first-ever daytime turbulence strength profile measurements at the observatory. We identified the presence of a strong turbulence layer ∼3 km above the observatory. The measured near-Earth turbulence matches the trend that is expected from the model for a daytime component of turbulence and gives an integrated r0 of ∼4 cm at 500 nm. This is consistent with earlier seeing measurements. This shows that a low-cost setup with a small telescope and a simple array of temperature sensors can be used for estimating the turbulence strength profile at the site.

中文翻译：

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科代卡纳尔天文台白天湍流强度剖面测量


印度天体物理研究所正在为科代卡纳尔塔望远镜开发多共轭自适应光学系统。在这种情况下，我们在科代卡纳尔天文台测量了白天的湍流强度剖面。第一种基于波前传感器图像的方法称为太阳差分图像运动监视器+，用于估计高度高达 5 至 6 公里的高空湍流。第二种方法使用气球载温度传感器来测量高达 350 m 的近地湍流。我们还进行了模拟来验证我们系统的性能。我们报告了天文台首次进行的白天湍流强度剖面测量。我们发现天文台上方约 3 公里处存在强湍流层。测得的近地湍流与模型对湍流白天部分的预期趋势相匹配，并给出了 500 nm 处的积分 r0 约为 4 cm。这与之前看到的测量结果一致。这表明，带有小型望远镜和简单的温度传感器阵列的低成本装置可用于估计现场的湍流强度剖面。