Modelling astronomical adaptive optics - I. The software package caos

• Published in: Monthly notices of the Royal Astronomical Society Vol. 356; no. 4; pp. 1263 - 1275
• Main Authors: Carbillet, M., Vérinaud, C., Femenía, B., Riccardi, A., Fini, L.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.02.2005; Blackwell Science; Oxford University Press (OUP): Policy P - Oxford Open Option A
• Subjects: Astrophysics; instrumentation: adaptive optics; instrumentation: high angular resolution; methods: numerical; Sciences of the Universe; telescopes; instrumentation: adaptive optics; Adaptive systems; Turbulence; Wave front; Atmosphere model; telescopes; Adaptive optics; Astronomical optics; instrumentation: high angular resolution -methods: numerical; Corrections; Interferometry
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2004.08524.x

The software package caos (code for adaptive optics systems) described in this paper is a software ensemble of modules designed for end-to-end simulation of generic astronomical adaptive optics (AO) systems, including a complete atmosphere turbulence model, sodium laser-guide star upward and downward propagation, observed object definition, Shack–Hartmann and novel pyramid wave-front sensors detailed modelling, wave-front reconstruction and subsequent time-filtering tools, and wave-front correction via different kinds of correctors; but also image formation, Fizeau interferometry, coronagraphy, etc. Consequently, it is more likely to be used as a tool dedicated to detailed optical astronomy studies than as an instrument simulator, as it is based on a wide range of unprecedented physical modelling. After a brief but global description, with particular emphasis on the most interesting physical modelling features, its use is illustrated through a chosen application, namely the question concerning the opportunity of having a tip–tilt-dedicated sensor in a 8-m class telescope pyramid-based AO system.