Layer-Oriented on paper, laboratory, and soon on the sky

Jacopo Farinato; Roberto Ragazzoni; Carmelo Arcidiacono; Bagnara Paolo; Andrea Baruffolo; Harald Baumeister; Raffaella Bisson; Hermann Bohnhardt; Angela Brindisi; Joar Brynnel; Massimo Cecconi; Julien Coyne; Bernhard Delabre; Emiliano Diolaiti; Rob Donaldson; Enrico Fedrigo; Francis Franza; Wolfgang Gassler; Adriano Ghedina; Thomas M. Herbst; Norbert N. Hubin; Stephan Kellner; Johann Kolb; Jean-Louis Lizon; Matteo Lombini; Enrico Marchetti; Gianluigi Meneghini; Lars Mohr; Roland Reiss; Ralf-Rainer Rohloff; Roberto Soci; Elise Vernet; Robert Weiss; Marco Xompero; Wenli Xu

doi:10.1117/12.566345

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7 July 2004 Layer-Oriented on paper, laboratory, and soon on the sky

Jacopo Farinato, Roberto Ragazzoni, Carmelo Arcidiacono, Bagnara Paolo, Andrea Baruffolo, Harald Baumeister, Raffaella Bisson, Hermann Bohnhardt, Angela Brindisi, Joar Brynnel, Massimo Cecconi, Julien Coyne, Bernhard Delabre, Emiliano Diolaiti, Rob Donaldson, Enrico Fedrigo, Francis Franza, Wolfgang Gassler, Adriano Ghedina, Thomas M. Herbst, Norbert N. Hubin, Stephan Kellner, Johann Kolb, Jean-Louis Lizon, Matteo Lombini, Enrico Marchetti, Gianluigi Meneghini, Lars Mohr, Roland Reiss, Ralf-Rainer Rohloff, Roberto Soci, Elise Vernet, Robert Weiss, Marco Xompero, Wenli Xu

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Proceedings Volume 5382, Second Backaskog Workshop on Extremely Large Telescopes; (2004) https://doi.org/10.1117/12.566345
Event: Second Backaskog Workshop on Extremely Large Telescopes, 2003, Backaskog, Sweden

Abstract

Layer Oriented represented in the last few years a new and promising aproach to solve the problems related to the limited field of view achieved by classical Adaptive Optics systems. It is basically a different approach to multi conjugate adaptive optics, in which pupil plane wavefront sensors (like the pyramid one) are conjugated to the same altitudes as the deformable mirrors. Each wavefront sensor is independently driving its conjugated deformable mirror thus simplifying strongly the complexity of the wavefront computers used to reconstruct the deformations and drive the mirror themselves, fact that can become very important in the case of extremely large telescopes where the complexity is a serious issue. The fact of using pupil plane wavefront sensors allow for optical co-addition of the light at the level of the detector thus increasing the SNR of the system and permitting the usage of faint stars, improving the efficiency of the wavefront sensor. Furthermore if coupled to the Pyramid wavefront sensor (because of its high sensitivity), this technique is actually peforming a very efficient usage of the light leading to the expectation that, even by using only natural guide stars, a good sky coverage can be achieved, above all in the case of giant telescopes. These are the main reasons for which in the last two years several projects decided to make MCAO systems based on the Layer Oriented technique. This is the case of MAD (an MCAO demonstrator that ESO is building with one wavefront sensing channel based on the Layer Oriented concept) and NIRVANA (an instrument for LBT). Few months ago we built and successfully tested a first prototype of a layer oriented wavefront sensor and experiments and demonstrations on the sky are foreseen even before the effective first light of the above mentioned instruments. The current situation of all these projects is presented, including the extensive laboratory testing and the on-going experiments on the sky.

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Jacopo Farinato, Roberto Ragazzoni, Carmelo Arcidiacono, Bagnara Paolo, Andrea Baruffolo, Harald Baumeister, Raffaella Bisson, Hermann Bohnhardt, Angela Brindisi, Joar Brynnel, Massimo Cecconi, Julien Coyne, Bernhard Delabre, Emiliano Diolaiti, Rob Donaldson, Enrico Fedrigo, Francis Franza, Wolfgang Gassler, Adriano Ghedina, Thomas M. Herbst, Norbert N. Hubin, Stephan Kellner, Johann Kolb, Jean-Louis Lizon, Matteo Lombini, Enrico Marchetti, Gianluigi Meneghini, Lars Mohr, Roland Reiss, Ralf-Rainer Rohloff, Roberto Soci, Elise Vernet, Robert Weiss, Marco Xompero, and Wenli Xu "Layer-Oriented on paper, laboratory, and soon on the sky", Proc. SPIE 5382, Second Backaskog Workshop on Extremely Large Telescopes, (7 July 2004); https://doi.org/10.1117/12.566345

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