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Image-based wavefront correction for space telescopes

  • With a view to future large space telescopes, we investigate image-based wavefront correction with active optics. We use an image-sharpness metric as merit function to evaluate the image quality, and the Zernike modes as control variables. In severely aberrated systems, the Zernike modes are not orthogonal to each other with respect to this merit function. Using wavefront maps, the PSF, and the MTF, we discuss the physical causes for the non-orthogonality of the Zernike modes with respect to the merit function. We show that for combinations of Zernike modes with the same azimuthal order, a flatter wavefront in the central region of the aperture is more important than the RMS wavefront error across the full aperture for achieving a better merit function. The non-orthogonality of the Zernike modes with respect to the merit function should be taken into account when designing the algorithm for image-based wavefront correction, because it may slow down the process or lead to premature convergence.
Author:Orestis Kazasidis, Sven Verpoort, Ulrich Wittrock
Parent Title (English):International Conference on Space Optics - ICSO 2018
Publisher:Proc. SPIE
Document Type:Conference Proceeding
Date of Publication (online):2019/07/23
Date of first Publication:2019/07/12
Publishing Institution:Fachhochschule M√ľnster - University of Applied Sciences
Release Date:2019/07/25
Tag:active optics, adaptive optics, sharpness metrics, aberration compensation, algorithm design
First Page:111807Z
Faculties:Physikingenieurwesen (PHY)
Publication list:Wittrock, Ulrich
Licence (German):License LogoZweitveroeffentlichung