Achievements 2013: Adaptive Optics

As mentioned in Telescopes and Mathematical Finance, we, together with the Industrial Mathematics Institute (Johannes Kepler Unibersität Linz) and the Radon Institute for Computational and Applied Mathematics (RICAM) of the Autrian Academy of Sciences, have been working on mathematical algorithms for Adaptive Optics for the last years. The achievements will be used in very large and extremely large ground-based telescopes.

Model of the European Extremely Large Telescope (E-ELT) which should go into operation in the early 2020s. Its primary mirror will have a diameter of 39 meters. Compare its size to that of the Munich football stadium.
The point spread function of a telescope describes, roughly speaking, how sharp an image can be under ideal conditions and, therefore, how well two distinct objects (think of a planet in the vicinity of a star) can be separated. When the primary mirror of a telescope gets larger, the point spread function gets closer to a delta distribution. This is the main reason for building extremely large telescopes.

The sharpness of the images is not only influenced by the point spread function but also by blurring through turbulences in the atmosphere. Adaptive optics uses deformable mirrors to correct blurred images.

If there were no atmosphere, the incoming wavefronts from a star to be observed would be parallel. The deformable mirror, optimally adjusted, corrects the perturbations. These perturbations change, more or less, continuously so that the actuator commands for the deformable mirror have to be calculated with a frequency of 500 to 3000 Hertz.

Next: SCAO, MCAO and MOAO.