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 /

Enhancing the efficiency of solar concentrators by controlled optical aberrations: Method and photovoltaic application

We present a general method, based on controlled static aberrations induced in the reflectors, to boost receiver performances in solar concentrators. Imaging mirrors coupled with dense arrays suffer from severe performance degradation since the solar irradiance distribution is bell-shaped: mismatch losses occur in particular when the cells are series connected. The method consists in computing static deformations of the reflecting surfaces that can produce, for an adopted concentration ratio, a light spot matching the receiver features better than conventional reflectors. The surfaces and the deformations have been analytically described employing the Zernike polynomials formalism. The concept here described can be applied to a variety of optical configurations and collecting areas. As an example, we extensively investigated a dense array photovoltaic concentrator, dimensioned for a nominal power of about 10 kWe. The "flat" distribution of light we obtain can exploit the PV device cells close to their efficiency limit. A significant gain is thus obtained, with no need of secondary optics or complex dish segmentation and of special features in the receiver electrical scheme. In the design, based on seven 2.6 m mirrors, we addressed also non-optical aspects as the receiver and the supporting mechanics. Optical and mechanical tolerances are demonstrated not to exceed accurate, but conventional, industrial standards

Possible application of FPGA to the MAORY Real Time Computer

MAORY is the post-focal Adaptive Optics module for the European Extremely Large Telescope first light. The baseline of MAORY is to rely upon the use of multiple Laser Guide Stars (6), multiple Natural Guide Stars (3) for wavefront sensing and multiple Deformable Mirrors (DM) for correction (M4/M5, that are part of the telescope, and 2 post focal DMs). The Real-Time Computer is a key sub-system of MAORY. It must collect the measurements from various sensing devices and drive several thousands actuators within high demanding latency requirements dictated by the system performance needs. The FPGA technology has been widely diffused in Real Time Systems due to its low latency and high determinism. Performance evaluation of this technology for the wavefront sensors images calibration and processing is in progress

MAORY real-time computer preliminary design

MAORY is the Multi-conjugate Adaptive Optics module for the Extremely Large Telescope and it will be located on the Nasmyth platform of the telescope to feed scientific instruments. MAORY will re-image the telescope focal plane providing multi-conjugate adaptive optics correction of the wavefront distortion induced by the atmosphere. The system is based on six laser guide stars and three natural guide stars for sensing the wavefront distortion and three deformable mirrors for correcting it. We will show the current status of the preliminary design of the Real Time Computer in charge of carrying out all the calculations based on the measurements of the guide stars wavefront sensors. The hard real time (primary) loops are in charge of controlling the deformable mirrors and the lasers jitter compensation while the soft real- time (secondary) loops are in charge of updating the primary loops parameters as well as measuring or estimating the atmospheric parameters and the system performance. Telemetry data management/recording and calibration are the other tasks carried out by the real time computer

The observing campaign on the deep-space debris WT1190F as a test case for short-warning NEO impacts

On 2015 November 13, the small artificial object designated WT1190F entered the Earth atmosphere above the Indian Ocean offshore Sri Lanka after being discovered as a possible new asteroid only a few weeks earlier. At ESA's SSA-NEO Coordination Centre we took advantage of this opportunity to organize a ground-based observational campaign, using WT1190F as a test case for a possible similar future event involving a natural asteroidal body. <P /

Numerical simulations of MAORY MCAO module for the ELT

MAO (MAORY Adaptive Optics) is the a developed numerical simulation tool for adaptive optics. It was created especially to simulate the performance of the MAORY MCAO module of the Extremely Large Telescope. It is a full end-to-end Monte-Carlo code able to perform different flavors of adaptive optics simulation. We used it to investigate the performance of a the MAORY and some specific issue related to calibration, acquisition and operation strategies. As, MAORY, MAO will implement Multi-conjugate Adaptive Optics combining Laser Guide Stars (LGS) and Natural Guide Stars (NGS) measurements. The implementation of the reference truth WFS completes the scheme. The simulation tool implements the various aspect of the MAORY in an end to end fashion. The code has been developed using IDL and use 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

A preliminary overview of the multiconjugate adaptive optics module for the E-ELT

ABSTRACT The multi-conjugate adaptive optics module for the European Extremely Large Telescope has to provide a corrected field of medium to large size (up to 2 arcmin), over the baseline wavelength range 0.8-2.4 µm. The current design is characterized by two post-focal deformable mirrors, that complement the correction provided by the adaptive telescope; the wavefront sensing is performed by means of a high-order multiple laser guide star wavefront sensor and by a loworder natural guide star wavefront sensor. The present status of a two years study for the advanced conceptual design of this module is reported