A Wavefront Sensorless Tip/Tilt Removal method for Correcting Astronomical Images

Abstract

Images of astronomical objects captured by ground-based telescopes are distorted due to atmospheric turbulence. The phase of the atmospheric aberration is traditionally estimated by a wavefront sensor (WFS). This information is utilised by a deformable mirror through a control system to restore the image. However, in this paper, we utilise wavefront sensorless (WFSL) methods in which the wavefront sensor is absent. Given that the largest share of atmospheric turbulence energy is contained in the 2-axial tilt for small aperture telescopes, we use WFSL to specifically remove these two modes. This method is shown to be efficient in terms of both speed and accuracy.