52 research outputs found
Historic evolution of the optical design of the Multi Conjugate Adaptive Optics Relay for the Extremely Large Telescope
The optical design of the Multi Conjugate Adaptive Optics Relay for the
Extremely Large Telescope experienced many modifications since Phase A
conclusion in late 2009. These modifications were due to the evolution of the
telescope design, the more and more accurate results of the performance
simulations and the variations of the opto-mechanical interfaces with both the
telescope and the client instruments. Besides, in light of the optics
manufacturing assessment feed-backs, the optical design underwent to a global
simplification respect to the former versions. Integration, alignment,
accessibility and maintenance issues took also a crucial role in the design
tuning during the last phases of its evolution. This paper intends to describe
the most important steps in the evolution of the optical design, whose
rationale has always been to have a feasible and robust instrument, fulfilling
all the requirements and interfaces. Among the wide exploration of possible
solutions, all the presented designs are compliant with the high-level
scientific requirements, concerning the maximum residual wavefront error and
the geometrical distortion at the exit ports. The outcome of this decennial
work is the design chosen as baseline at the kick-off of the Phase B in 2016
and subsequently slightly modified, after requests and inputs from alignment
and maintenance side
Laboratory Testing the Layer Oriented Wavefront Sensor for the Multiconjugate Adaptive optics Demonstrator
The Multiconjugate Adaptive optics Demonstrator (MAD) for ESO-Very Large
Telescopes (VLT) will demonstrate on sky the MultiConjugate Adaptive Optics
(MCAO) technique. In this paper the laboratory tests relative to the first
preliminary acceptance in Europe of the Layer Oriented (LO) Wavefront Sensor
(WFS) for MAD will be described: the capabilities of the LO approach have been
checked and the ability of the WFS to measure phase screens positioned at
different altitudes has been experimented. The LO WFS was opto-mechanically
integrated and aligned in INAF - Astrophysical Observatory of Arcetri before
the delivering to ESO (Garching) to be installed on the final optical bench.
The LO WFS looks for up to 8 reference stars on a 2arcmin Field of View and up
to 8 pyramids can be positioned where the focal spot images of the reference
stars form, splitting the light in four beams. Then two objectives conjugated
at different altitudes simultaneously produce a quadruple pupil image of each
reference star.Comment: 12 pages,14 figures, Proceeding of Spie Conference "Advances in
Adaptive Optics II", Orlando 200
Optical design of the Post Focal Relay of MAORY
The Multi Conjugate Adaptive Optics Relay (MAORY) for the European Extremely Large Telescope shall re-image the telescope focal plane for the client instruments installed on two exit ports. By means of natural and artificial (laser) reference sources for wavefront sensing, and of deformable mirrors for wavefront correction, MAORY shall be able to compensate the wavefront disturbances affecting the scientific observations, achieving high Strehl ratio and high sky coverage. The optical interfaces to the client instruments must replicate the telescope one while the volume allocation on the Nasmyth platform is under definition at the moment of this writing. We show the latest version of the optical design that matches the current requests and its optical performance. The laser guide stars channel, separated from the science path by means of a dichroic beam-splitter, is also presented. <P /
An update of the on-sky performance of the Layer-Oriented wave-front sensor for MAD
The Multi-conjugate Adaptive optics Demonstrator, MAD, successfully
demonstrated on sky the MCAO technique both in Layer Oriented and Star Oriented
modes. As results of the Guaranteed Time Observations in Layer Oriented mode
quality astronomy papers have been published. In this paper we concentrate on
the instrumentation issues and technical aspects which stay behind this
success.Comment: 12 pages, 10 figures, Proceedings of the SPIE conference "Adaptive
Optics Systems II", 27 June 2010, San Diego, California, US
End to end numerical simulations of the MAORY multiconjugate adaptive optics system
MAORY is the adaptive optics module of the E-ELT that will feed the MICADO
imaging camera through a gravity invariant exit port. MAORY has been foreseen
to implement MCAO correction through three high order deformable mirrors driven
by the reference signals of six Laser Guide Stars (LGSs) feeding as many
Shack-Hartmann Wavefront Sensors. A three Natural Guide Stars (NGSs) system
will provide the low order correction. We develop a code for the end-to-end
simulation of the MAORY adaptive optics (AO) system in order to obtain
high-delity modeling of the system performance. It is based on the IDL language
and makes extensively uses of the GPUs. Here we present the architecture of the
simulation tool and its achieved and expected performance.Comment: 8 pages, 4 figures, presented at SPIE Astronomical Telescopes +
Instrumentation 2014 in Montr\'eal, Quebec, Canada, with number 9148-25
The numerical simulation tool for the MAORY multiconjugate adaptive optics system
The Multiconjugate Adaptive Optics RelaY (MAORY) is and Adaptive Optics
module to be mounted on the ESO European-Extremely Large Telescope (E-ELT). It
is a hybrid Natural and Laser Guide System that will perform the correction of
the atmospheric turbulence volume above the telescope feeding the Multi-AO
Imaging Camera for Deep Observations Near Infrared spectro-imager (MICADO). We
developed an end-to-end Monte- Carlo adaptive optics simulation tool to
investigate the performance of a the MAORY and the calibration, acquisition,
operation strategies. MAORY will implement Multiconjugate Adaptive Optics
combining Laser Guide Stars (LGS) and Natural Guide Stars (NGS) measurements.
The simulation tool implements the various aspect of the MAORY in an end to end
fashion. The code has been developed using IDL and uses libraries in C++ and
CUDA for efficiency improvements. Here we recall the code architecture, we
describe the modeled instrument components and the control strategies
implemented in the code.Comment: 6 pages, 1 figure, Proceeding 9909 310 of the conference SPIE
Astronomical Telescopes + Instrumentation 2016, 26 June 1 July 2016
Edinburgh, Scotland, U
Laboratory prototype for the demonstration of sodium laser guide star wavefront sensing on the E-ELT
The new class of Extremely Large Telescopes (ELT) relies on Sodium Laser Guide Stars (LGS) to improve the Adaptive Optics performance in terms of correction quality and sky coverage. The time instability and the vertical extension of the atmospheric Sodium layer density have a potential significant impact on the wavefront sensing accuracy. We describe a laboratory prototype which has been developed with the goal to investigate specific algorithms for wavefront sensing with these artificial sources under different conditions of sodium layer density profile, parallactic effects due to laser launch geometry and atmospheric turbulence. The prototype can emulate realistic elongated spots on the focal plane of a Shack-Hartmann wavefront sensor (SHWFS), including their intensity variations due to the time variability of the Sodium density vertical profile. In addition, multiple LGSs can be simulated, one at a time, and a two-layer atmospheric turbulence model is available. Herein we report the verification of prototype performances, including optical performance, accuracy of emulated Sodium density profiles and atmospheric turbulence features. <P /
Modelling the multi-conjugate adaptive optics system of the European Extremely Large Telescope
MAORY is the Multi-Conjugate Adaptive Optics Module for the E-ELT. The baseline design assumes six sodium Laser Guide Stars and three Natural Guide Stars for wavefront sensing. Three deformable mirrors, including the telescope adaptive mirror M4, are optically conjugated to different altitudes in the atmosphere to achieve compensation of the atmospheric turbulence effects over an extended Field of View. In preparation for the project phase-B we are analyzing different critical aspects of such a system. We are developing a versatile and modular end-to-end simulation code that makes use of GPUs to obtain high-fidelity modelling of the system performance and, in parallel, a semplified code for the analysis of the effects induced by the temporal variation of the sodium layer where the artificial laser guide stars are generated. An overview of the work in progress will be given. <P /
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