A comprehensive suite of Adaptive Optics systems and AO-assisted instruments is currently under development for the VLT and will be built around a hyperbolic convex adaptive Deformable Secondary Mirror (DSM). In telescopes with such a secondary mirror, test and calibration of both the DSM and the science instruments using it are notoriously expensive and time-consuming. The Adaptive Secondary Setup and Instrument Stimulator (ASSIST) is being developed to allow test and integration of three key elements of the future VLT Adaptive Telescope Facility: the DSM and 2 instrument-specific adaptive optics systems (GALACSI for MUSE and GRAAL for HAWK-I). The core of ASSIST is a standalone interferometric test setup for the DSM allowing its test at its center of curvature (significantly reducing the size of the classical hyperbole focii test configuration). This setup is completed by a star simulator for both natural and laser guide stars, a turbulence generator (for realistic AO performance measurements), a corrector system generating a VLT-like exit pupil and a Nasmyth rotator simulator interfacing with the two AO systems. In this paper we present the optical architecture of ASSIST, detailing the current design of the different parts of the system, and discuss its projected performance and compliance with the test and calibration requirements.

Secondary mirror

Deformable Mirror

10.1117/12.680560

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Statu so fA daptiv eO ptics Projects at ES O

N. Hubin

This paper wil lr eview all Adaptiv eO ptics systems already in operation or in construction at ESO. Roadmap toward the future AO systems both for the VL T and for OW Lw ill be discussed.

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<title>Performance and results of the COME-ON+ adaptive optics system at the ESO 3.6-m telescope</title>

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (1994)

Gérard Rousset Jean-Luc Beuzit N. Hubin É. Gendron Pierre-Yves Madec

The COME-ON+ adaptive optics system was set up on the ESO 3.6-meter telescope for two technical runs (in December 1992 and April 1993) and is now routinely used for astronomical observations. This system is an upgrade of the COME-ON adaptive optics prototype system. During the technical runs, images were recorded in the V, I, J, K and L' spectral bands. Currently, the best resolution obtained is 0.1' in H (1.65 micrometers ) under bad seeing conditions (seeing > 1' and averaged wind speed > 10 m/s) and reference star magnitudes of 6 to 8. The corresponding Strehl ratio is 35%. 70% Strehl ratio was obtained at 2.2 micrometers (K band). At 0.9 micrometers (I band), in the partial correction regime, the resolution is of the order of 0.2' for 0.8' seeing and 10 m/s averaged wind speed. The optimized modal control has been used on faint reference stars. The limiting magnitude (in V band) for wavefront sensing has been measured to 14 and 15 depending on the spectral type of the reference star and the seeing conditions for a low frequency tip-tilt correction.

Strehl ratio

Guide star

Limiting magnitude

Laser Guide Star

Spectral resolution

Wavefront sensor

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Very Large Telescope

Deformable Mirror

10.1117/12.176020

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EPICS: direct imaging of exoplanets with the E-ELT

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2010)

M. Kasper Jean-Luc Beuzit Christophe Vérinaud R. Gratton F. Kerber

Presently, dedicated instruments at large telescopes (SPHERE for the VLT, GPI for Gemini) are about to discover and explore self-luminous giant planets by direct imaging and spectroscopy. The next generation of 30m-40m ground-based telescopes, the Extremely Large Telescopes (ELTs), have the potential to dramatically enlarge the discovery space towards older giant planets seen in reflected light and ultimately even a small number of rocky planets. EPICS is a proposed instrument for the European ELT, dedicated to the detection and characterization of Exoplanets by direct imaging, spectroscopy and polarimetry. ESO completed a phase-A study for EPICS with a large European consortium which - by simulations and demonstration experiments - investigated state-of-the-art diffraction and speckle suppression techniques to deliver highest contrasts. The paper presents the instrument concept and analysis as well as its main innovations and science capabilities. EPICS is capable of discovering hundreds of giant planets, and dozens of lower mass planets down to the rocky planets domain.

Direct imaging

10.1117/12.856850

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Citations (65)

ESO adaptive optics facility progress and first laboratory test results

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2014)

Robin Arsenault Pierre-Yves Madec J. Paufique P. La Penna Stefan Stroebele

The Adaptive Optics Facility project is completing the integration of its systems at ESO Headquarters in Garching. The main test bench ASSIST and the 2^nd Generation M2-Unit (hosting the Deformable Secondary Mirror) have been granted acceptance late 2012. The DSM has undergone a series of tests on ASSIST in 2013 which have validated its optical performance and launched the System Test Phase of the AOF. This has been followed by the performance evaluation of the GRAAL natural guide star mode on-axis and will continue in 2014 with its Ground Layer AO mode. The GALACSI module (for MUSE) Wide-Field-Mode (GLAO) and the more challenging Narrow-Field-Mode (LTAO) will then be tested. The AOF has also taken delivery of the second scientific thin shell mirror and the first 22 Watt Sodium laser Unit. We will report on the system tests status, the performances evaluated on the ASSIST bench and advancement of the 4Laser Guide Star Facility. We will also present the near future plans for commissioning on the telescope and some considerations on tools to ensure an efficient operation of the Facility in Paranal.

Laser Guide Star

First light

Secondary mirror

Mode (computer interface)

Test bench

Guide star

Active optics

10.1117/12.2054859

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The HIP 79977 debris disk in polarized light

Astronomy and Astrophysics (2017)

N. Engler H. M. Schmid Ch. Thalmann A. Boccaletti A. Bazzon

We present observations of the known edge-on debris disk around HIP 79977 (HD 146897, F star in Upper Sco, 123 pc), taken with the ZIMPOL differential polarimeter of the SPHERE instrument in the Very Broad Band filter ($\lambda_c=735$ nm, $\Delta\lambda=290$ nm) with a spatial resolution of about 25 mas. We measure the polarization flux along and perpendicular to the disk spine of the highly inclined disk for projected separations between 0.2" (25 AU) and 1.6" (200 AU) and investigate the diagnostic potential of such data with model simulations. The polarized flux contrast ratio for the disk is $F_{pol}/F_\ast= (5.5 \pm 0.9) 10^{-4}$. The surface brightness reaches a maximum of 16.2 mag arcsec$^{-2}$ at a separation of $0.2"-0.5"$ along the disk spine with a maximum surface brightness contrast of 7.64 mag arcsec$^{-2}$. The polarized flux has a minimum near the star $<0.2"$ because no or only little polarization is produced by forward or backward scattering in the disk section lying in front of or behind the star. The data are modeled as a circular dust belt with an inclination $i=85(\pm 1.5)^\circ$ and a radius between $r_0$ = 60 AU and 90 AU. The radial density dependence is described by $(r/r_0)^{\alpha}$ with a steep power law index $\alpha=5$ inside $r_0$ and a more shallow index $\alpha=-2.5$ outside $r_0$. The scattering asymmetry factor lies between $g$ = 0.2 and 0.6 adopting a scattering angle-dependence for the fractional polarization as for Rayleigh scattering. Our data are qualitatively very similar to the case of AU Mic and they confirm that edge-on debris disks have a polarization minimum at a position near the star and a maximum near the projected separation of the main debris belt. The comparison of the polarized flux contrast ratio $F_{pol}/F_{\ast}$ with the fractional infrared excess provides strong constraints on the scattering albedo of the dust.

Debris disk

Position angle

10.1051/0004-6361/201730846

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Citations (51)

First light of SINFONI at the VLT

The Messenger (2004)

Henri Bonnet R. Abuter A. J. Baker W. Bornemann A. G. A. Brown

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Adaptive optics simulations for the European Extremely Large Telescope

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2006)

Miska Le Louarn Christophe Vérinaud Visa Korkiakoski N. Hubin Enrico Marchetti

In this article we summarize the parameter space exploration for several adaptive optics systems for a 42-m European Extremely Large Telescope. These systems are modular, and based on a various number of identical high order wavefront sensor. We explore a single natural guide star single conjugate AO and multi-laser guide star systems: ground-layer AO, laser-tomography AO, and multi-conjugate AO. The performance estimates are given in terms of Strehl ratio or, for the GLAO system in terms of ensquared energy.

Strehl ratio

Laser Guide Star

Deformable Mirror

Wavefront sensor

Guide star

10.1117/12.670187

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Citations (31)

<title>ADONIS: a user-friendly adaptive optics system for the ESO 3.6-m telescope</title>

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (1994)

Jean-Luc Beuzit N. Hubin É. Gendron Laurent Demailly P. Gigan

ADONIS (ADaptive OPtics Near Infrared System) is an upgrade of the COME-ON+ adaptive optics prototype. It will allow the astronomical community to use adaptive optics as a common user instrument. This paper describes the main features of the new system, including a mechanical and optical interface for specific visitor equipment and imaging capabilities. We present here the 128 X 128 infrared imaging camera, covering the 1 - 5 micrometers spectral range.

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Adonis

Visitor pattern

10.1117/12.176129

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Citations (11)