The M4 adaptive unit for the E-ELT

B. Crépy; S. Chaillot; JM Conan; R. Cousty; C. Delrez; M. Dimmler; JL Dournaux; S. De Zotti; E. Gabriel; R. Gasmi; R. Grasser; N. Hubin; P. Jagourel; L. Jochum; F. Locre; P-Y Madec; P. Morin; M. Mueller; G. Petit; D. Petitgas; JJ Roland; JC Sinquin; E. Vernet

doi:10.1051/ao4elt/201006001

All issues

Year: 2010

10.1051/ao4elt/201006001

Abstract

Open Access

Issue		2010


Article Number		06001
Number of page(s)		6
Section		Deformable mirrors
DOI		https://doi.org/10.1051/ao4elt/201006001
Published online		24 February 2010

1st AO4ELT conference, 06001 (2010)

The M4 adaptive unit for the E-ELT

B. Crépy^(b), S. Chaillot^(g), JM Conan^(d), R. Cousty^(b), C. Delrez^(c), M. Dimmler^(a), JL Dournaux^(f), S. De Zotti^(e), E. Gabriel^(c), R. Gasmi^(f), R. Grasser^(b), N. Hubin^(a), P. Jagourel^(f), L. Jochum^(a), F. Locre^(b), P-Y Madec^(a), P. Morin^(b), M. Mueller^(a), G. Petit^(d), D. Petitgas^(b), JJ Roland^(b), JC Sinquin^(b) and E. Vernet^(a)

^(a) ESO Karl-Schwarzschild-Strasse 2 - D-85748 Garching bei München
^(b) CILAS, 8 Avenue Buffon – BP 6319 - 45063 Orléans Cedex, France
^(c) AMOS Liege science park - Rue des Chasseurs Ardennais - 4031 Angleur, Belgium
^(d) ONERA BP72 - 29 avenue de la Division Leclerc - FR-92322 - Chatillon, France
^(e) Astrium, 31, avenue des Cosmonautes - 31402 Toulouse, France
^(f) Observatory of Paris Meudon , 5, place Jules Janssen, 92195 Meudon, France
^(g) Boostec, Zone Industrielle - 65460 Bazet, France

Abstract

Cilas proposes a M4 adaptive mirror (M4AM) that corrects the atmospheric turbulence at high frequencies and residual tip-tilt and defocus due to telescope vibrations by using piezostack actuators. The design presents a matrix of nearly 7000 actuators (hexagonal geometry, spacing equal to 29 mm) leading to a fitting error simulated by Onera reaching the fitting error goal. The mirror is held by a positioning system which ensures all movements of the mirror at low frequency and selects the focus (Nasmyth A or B) using a hexapod concept. This subsystem is fixed rigidly to the mounting system and permits mirror displacements. The M4 control system (M4CS) ensures the connection between the telescope control/monitoring system and the M4 unit - positioning system (M4PS) and piezostack actuators in particular. This subsystem is composed of electronic boards, mechanical support fixed to the mounting structure and the thermal hardware. With piezostack actuators, most of the thermal load is minimized and dissipated in the electronic boards and not in the adaptive mirror. The mounting structure (M4MS) is the mechanical interface with the telescope (and the ARU in particular) and ensures the integrity and stability of M4 unit subsystems. M4 positioning system and mounting structure are subcontracted to Amos company. We will also report on the manufacturing of the demonstration prototype that will be tested in the next phase. Keywords: Adaptive optic, Adaptive unit, E-ELT, hexapod, mirror, PZT actuator

Key words: Adaptive optic / Adaptive unit / E-ELT / hexapod / mirror / PZT actuator