Guest speaker Prof.dr. R. Ramlau from Johannes Kepler University Linz

13 December 2018 15:30 till 16:15 - Location: lecture room F, 3me - By: DCSC

"Wavefront reconstruction from Pyramid Sensor Data"

The image quality of ground based astronomical telescopes suffers from turbulences in the atmosphere. Adaptive Optics (AO) systems use wavefront sensor measurements of incoming light from guide stars to determine an optimal shape of deformable mirrors (DM) such that the image of the scientific object is corrected after reection on the DM(s). The operation of the AO systems of the new generation of large astronomical telescopes under construction requires new mathematical methods, in particular for wavefront reconstruction and atmospheric tomography.
In our talk we will in particular focus on the Pyramid sensor, which has been chosen as wavefront sensor for several of the instruments of the Extremely Large Telescope (ELT) of the European Southern Observatory (ESO). A nonlinear mathematical model for the Pyramid sensor as well as suitable linearizations will be developed and analyzed. We additionally introduce algorithms based on the linear/nonlinear models that achieve reconstructions of high quality. We will additionally consider the case where the measured data is segmented by the telescope's support structure for the secondary mirror. Numerical results demonstrate the feasibility of our reconstructors for operation on the telescope. 

Guest of: M. Verhaegen