Hierarchichal-segmented AO in order to attain wide field compensation in the visible on an 8m class telescope

TL;DR

This paper proposes a hierarchical segmented adaptive optics system for 8-meter class telescopes, enabling wide field correction by combining ground-layer and high-altitude corrections with flexible, tunable parameters.

Contribution

It introduces a novel optical layout for a segmented AO system that integrates ground-layer and open-loop high-altitude corrections, with adaptable field of view and wavefront sensing strategies.

Findings

Variable field of view matching turbulence conditions

Feasibility of wavefront sensing with natural and artificial references

Preliminary optomechanical design and effort estimates

Abstract

We describe the preliminary optimized layout for a partially optimized concept of an optical-8m class VLT-like 2x2 segmented camera where each channel is assisted by an equivalent of an MCAO system where the ground layer correction is commonly employed while the high altitude ones is performed in an open-loop fashion. While we derive the basic relationships among the Field of View and attainable correction with a pre-defined choice for the hardware, we discuss sky coverage and wavefront sensing issues employing natural and artificial references, involving the latest stateof-the-art in the development of wavefront sensing. We show that a flexible approach allow for a compensated Field of View that is variable and can be properly tuned matching the current turbulence situation and the requirement in term of quality of the compensation. A preliminary description of the overall optomechanical package is given as well along with a rough estimates of the efforts required to translates such a concept into reality.