10 July 2008 Cornelis Zwaan, open principle, and the future of high-resolution solar telescopes
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It was in the years around 1970 that during site-test campaigns for JOSO masts were erected up till 30 m height with sensors at several heights for the measurement of temperature fluctuations. Cornelis (Kees) Zwaan discovered that the fluctuations decrease drastically at heights from about 15 m and upward when there is some wind. The conclusion from this experience was the open telescope principle: the telescope should be completely free in the air 15 m or more above the ground. The Dutch Open Telescope (DOT) was the pioneering demonstrator of the open-telescope technology. Now that larger high-resolution telescopes come in view, it is time to analyze again the principle: (i) the essentials for proper working of the open principle; (ii) the differences with nighttime observations particularly concerning the seeing; (iii) the design consequences for the new generation of high-resolution solar telescopes.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Robert H. Hammerschlag, Robert H. Hammerschlag, Felix C. M. Bettonvil, Felix C. M. Bettonvil, Aswin P. L. Jägers, Aswin P. L. Jägers, Guus Sliepen, Guus Sliepen, } "Cornelis Zwaan, open principle, and the future of high-resolution solar telescopes", Proc. SPIE 7012, Ground-based and Airborne Telescopes II, 70120M (10 July 2008); doi: 10.1117/12.789944; https://doi.org/10.1117/12.789944


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