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

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

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 /

A method for space-variant deblurring with application to adaptive optics imaging in astronomy

Images from adaptive optics systems are generally affected by significant distortions of the point spread function (PSF) across the field of view, depending on the position of natural and artificial guide stars. Image reduction techniques circumventing or mitigating these effects are important tools to take full advantage of the scientific information encoded in AO images. The aim of this paper is to propose a method for the deblurring of the astronomical image, given a set of samples of the space-variant PSF. The method is based on a partitioning of the image domain into regions of isoplanatism and on applying suitable deconvolution methods with boundary effects correction to each region. The effectiveness of the boundary effects correction is proved. Moreover, the criterion for extending the disjoint sections to partially overlapping sections is validated. The method is applied to simulated images of a stellar system characterized by a spatially variable PSF. We obtain good photometric quality, and therefore good science quality, by performing aperture photometry on the deblurred images. The proposed method is implemented in IDL in the Software Package "Patch", which is available on http://www.airyproject.eu.Comment: 11 pages, 9 figures, 7 tables, accepted by A&

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

LOST - Layer Oriented Simulation Tool

The Layer-Oriented Simulation Tool (LOST) is a code for simulating the performance of multiconjugate adaptive optics modules that uses a layer-oriented approach. It calculates atmospheric layers as phase screens, and then calculates the phase delays caused by these screens on the wave fronts of natural guide stars through geometrical optics approximations. This simulation considers the impact of wave-front sensors on measurement phase noise when combining wave fronts optically or numerically. The LOST code is explained in a dedicated publication. It was used for the estimation of the performance of the two layer-oriented modules MAD and NIRVANA, specifically the Multiconjugate Adaptive Optics Demonstrator for the Very Large Telescope and the Near-IR-Visible Adaptive Interferometer for Astronomy for the Large Binocular Telescope

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

Stellar photometry with Multi Conjugate Adaptive Optics

We overview the current status of photometric analyses of images collected with Multi Conjugate Adaptive Optics (MCAO) at 8-10m class telescopes that operated, or are operating, on sky. Particular attention will be payed to resolved stellar population studies. Stars in crowded stellar systems, such as globular clusters or in nearby galaxies, are ideal test particles to test AO performance. We will focus the discussion on photometric precision and accuracy reached nowadays. We briefly describe our project on stellar photometry and astrometry of Galactic globular clusters using images taken with GeMS at the Gemini South telescope. We also present the photometry performed with DAOPHOT suite of programs into the crowded regions of these globulars reaching very faint limiting magnitudes Ks ~21.5 mag on moderately large fields of view (~1.5 arcmin squared). We highlight the need for new algorithms to improve the modeling of the complex variation of the Point Spread Function across the field of view. Finally, we outline the role that large samples of stellar standards plays in providing a detailed description of the MCAO performance and in precise and accurate colour{magnitude diagrams.Comment: 17 pages, 12 figures, SPIE 201