Wavefront sensing with a brightest pixel selection algorithm

Abstract

Astronomical adaptive optics systems with open-loop deformable mirror control have recently come on-line. In these systems, the deformable mirror surface is not included in the wavefront sensor paths, and so changes made to the deformable mirror are not fed back to the wavefront sensors. This gives rise to all sorts of linearity and control issues mainly centred on one question: Has the mirror taken the shape requested? Non-linearities in wavefront measurement and in the deformable mirror shape can lead to significant deviations in mirror shape from the requested shape. Here, wavefront sensor measurements made using a brightest pixel selection method are discussed along with the implications that this has for open-loop AO systems. Discussion includes elongated laser guide star spots and also computational efficiency.

10 pages, 12 figures, accepted by MNRAS

References in corpus (2)

• A search for hot massive extrasolar planets around nearby young stars with the adaptive optics system NACO
• Radial thresholding to mitigate Laser-Guide-Star aberrations on Centre-of-Gravity-based Shack-Hartmann wavefront sensors

Cited by in corpus (9)

• AOtools -- a Python package for adaptive optics modelling and analysis
• Demonstrating 24-hour continuous vertical monitoring of atmospheric optical turbulence
• Analysis of on-sky MOAO performance of CANARY using natural guide stars
• Monte-Carlo simulation of ELT scale multi-object adaptive optics deformable mirror requirements and tolerances
• Real-time correlation reference update for astronomical adaptive optics
• A real-time simulation facility for astronomical adaptive optics
• Wide-field adaptive optics performance in cosmological deep fields for multi-object spectroscopy with the European Extremely Large Telescope
• Wave-front error breakdown in LGS MOAO validated on-sky by CANARY
• Sensitivity improvements for Shack-Hartmann wavefront sensors using total variation minimisation