MCAO for the E-ELT: preliminary design overview of the MAORY module

¹ Università di Bologna Dipartimento di Astronomia, via Ranzani 1, 40127 Bologna, Italy
² INAF - Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
³ INAF - Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, 35122 Padova, Italy
⁴ INAF - Osservatorio Astrofisico di Arcetri, largo E. Fermi 5, 50125 Firenze, Italy
⁵ ESO European Organisation for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2, 85748 Garching bei Munchen, Germany
⁶ ONERA Office National d'Etudes et de Recherches Aerospatiales, B.P. 72, 92322 Chatillon, France

^a e-mail: italo.foppiani@unibo.it

Abstract

MAORY is the Multi-conjugate Adaptive Optics RelaY module for the European Extremely Large Telescope. It will be located on the Nasmyth platform of the telescope to feed scientific instruments. The module is supposed to re-image one to one the telescope focal plane with diffraction limited optical quality and to provide multi-conjugate adaptive optics correction of the wavefront distortion induced by the atmosphere. The system is based on six laser guide stars for sensing the wavefront distortion and three deformable mirrors for correcting it. A dichroic is used to split the laser light from the light of the scientific and natural guide stars channel. Two output ports, selected by the dichroic orientation, are foreseen: one in a gravity invariant configuration and one in a vertical position to feed large instruments. In this article the current optical and mechanical design are presented together with the thermal analysis.