A parametric model of wind buffeting on an extremely large telescope with a multipod secondary support is described. The model estimates wave-front errors that are due to wind buffeting on a segmented primary, wind-induced secondary figure and position errors, and primary-mirror deformations caused by wind forces on the secondary support. The approach is based on a Zernike expansion of pressure fluctuations, with simple models of stiffness, resonance, and control. The model shows that wind buffeting on a multipod attached to the primary mirror cell significantly degrades the image quality in a large telescope with a slow primary.
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