The Multi-Conjugate Adaptive Optics Demonstrator (MAD) is a prototype MCAO system which aims to demonstrate in the laboratory and on sky the feasibility of different MCAO image reconstruction and correction techniques in view of future applications with the 2nd Generation VLT Instruments and E-ELT instrumentation.

MAD is designed to perform wide field of view (FoV) adaptive optics correction in K band (2.2 um) over 2 arcmin on the sky by using relatively bright (mv < 12) Natural Guide Stars. The MCAO correction is implemented by using two Deformable Mirrors, one optically conjugated at the telescope pupil (ground layer turbulence correction) and the second one conjugated at 8.5 Km above the telescope aperture for the correction of the field anisoplanatism. The wavefront sensor actually installed on the MAD is based on three Shack-Hartmann wavefront sensors allowing to pick-up three natural guide stars on the full 2 arcmin FoV (round). A second type of wavefront sensor called Layer Oriented will be installed and operated during the last demonstration run planned for late September 2007.

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