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1. Speckle lifetime in XAO coronagraphic images: temporal evolution of SPHERE coronagraphic images

Author

Milli, J., Banas, T., Mouillet, D., Mawet, D., Girard, J. H., Vigan, Arthur, Boccaletti, A., Kasper, M., Wahhaj, Zahed, Lagrange, A. M., Beuzit, J.-L., Fusco, T., Sauvage, J.-F., Galicher, R., Marchetti, Enrico, Close, Laird, Véran, Jean-Pierre, European Southern Observatory (ESO), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), European Southern Observatory [Santiago] (ESO), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NRC Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Marchetti, Enrico, Close, Laird M., and Véran, Jean-Pierre

Subjects
Physics, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, 01 natural sciences, Exoplanet, 010309 optics, Speckle pattern, Optics, 0103 physical sciences, Atmospheric turbulence, Astrophysics::Earth and Planetary Astrophysics, Spatial dependence, Astrophysics - Instrumentation and Methods for Astrophysics, Adaptive optics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Decorrelation, Instrumentation and Methods for Astrophysics (astro-ph.IM), Data reduction
Abstract

The major source of noise in high-contrast imaging is the presence of slowly evolving speckles that do not average with time. The temporal stability of the point-spread-function (PSF) is therefore critical to reach a high contrast with extreme adaptive optics (xAO) instruments. Understanding on which timescales the PSF evolves and what are the critical parameters driving the speckle variability allow to design an optimal observing strategy and data reduction technique to calibrate instrumental aberrations and reveal faint astrophysical sources. We have obtained a series of 52 min, AO-corrected, coronagraphically occulted, high-cadence (1.6Hz), H-band images of the star HR 3484 with the SPHERE (Spectro-Polarimeter High-contrast Exoplanet REsearch instrument on the VLT. This is a unique data set from an xAO instrument to study its stability on timescales as short as one second and as long as several tens of minutes. We find different temporal regimes of decorrelation. We show that residuals from the atmospheric turbulence induce a fast, partial decorrelation of the PSF over a few seconds, before a transition to a regime with a linear decorrelation with time, at a rate of several tens parts per million per second (ppm/s). We analyze the spatial dependence of this decorrelation, within the well-corrected radius of the adaptive optics system and show that the linear decorrelation is faster at short separations. Last, we investigate the influence of the distance to the meridian on the decorrelation., Comment: 18 pages, 20 figures

Published
2016
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2. Tackling down the low wind effect on SPHERE instrument

Author

Sauvage, Jean-François, Fusco, Thierry, Lamb, Masen, Girard, Julien, Brinkmann, Martin, Guesalaga, Andrés, Wizinowich, Peter, O'Neal, Jared, N'Diaye, Mamadou, Vigan, Arthur, Mouillet, David, Beuzit, Jean-Luc, Kasper, Markus, Le Louarn, Miska, Milli, Julien, Dohlen, Kjetil, Neichel, Benoit, Bourget, Pierre, Haguenauer, Pierre, Mawet, Dimitri, Marchetti, Enrico, Close, Laird, Véran, Jean-Pierre, Vigan, Arthur, DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), European Southern Observatory (ESO), Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Universidad Católica de la Santísima Concepción (UCSC), W.M. Keck Observatory, Space Telescope Science Institute (STSci), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), ONERA - The French Aerospace Lab [Châtillon], Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory [Santiago] (ESO), California Institute of Technology (CALTECH), NRC Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), ONERA, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Marchetti, Enrico, Close, Laird M., and Véran, Jean-Pierre

Subjects
Physics, Wavefront, business.industry, media_common.quotation_subject, Strehl ratio, 01 natural sciences, Exoplanet, law.invention, 010309 optics, Telescope, Wavelength, Optics, law, Sky, Planet, 0103 physical sciences, Adaptive optics, business, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Remote sensing, media_common
Abstract

International audience; SPHERE is the VLT second generation planet hunter instrument. Installed since May 2014 on UT3, the system has been commissioned and verified for more than one year now and routinely delivers unprecedented images of star surroundings, exoplanets and dust disks. The exceptional performance required for this kind of observation makes the appointment: a repeatable Strehl Ratio of 90% in H band, a rough contrast level of 10-5@0.5 arcsec, and reaches 10-6 at the same separation after differential imaging (SDI, ADI). The instrument also presents high contrast levels in the visible and an unprecedented 17mas diffraction-limited resolution at 0.65 microns wavelength. SAXO is the SPHERE XAO system, allowing the system to reach its final detectivity. Its high performance and therefore highly sensitive capacities turns a new eye on telescope environment. Even if XAO performance are reached as expected, some unexpected limitations are here described and a first work around is proposed and discussed. Spatial limitation: wave-front aberrations have been identified, deviating from kolmogorov statistics, and therefore not easily seen and compensated for by the XAO system. The impact of this limitations results in a degraded performance in some particular low wind conditions. Solutions are developed and tested on sky to propose a new operation procedure reducing this limitation. Temporal limitation: high amplitude vibrations on the low order modes have been issued, due to telescope environment and XAO behaviour. Again, a solution is developed and an assessment of its performance is dressed. The potential application of these solutions to E-ELT is proposed.

Published
2016
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3. The adaptive optics modes for HARMONI: from Classical to Laser Assisted Tomographic AO

Author

Neichel, B., Fusco, T., Sauvage, J. -F., Correia, C., Dohlen, K., El-Hadi, K., Blanco, L., Schwartz, N., Clarke, F., Thatte, N., Tecza, M., Paufique, J., Vernet, J., Louarn, M. Le, Hammersley, P., Gach, J. -L., Pascal, S., Vola, P., Petit, C., Conan, J. -M., Carlotti, A., Verinaud, C., Schnetler, H., Bryson, I., Morris, T., Myers, R., Hugot, E., Gallie, A., Marchetti, Enrico, Close, Laird, Véran, Jean-Pierre, Le Louarn, M., Gach, L., Conan, M., Vérinaud, C., Gallie, M., Henry, M., Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), ONERA - The French Aerospace Lab [Châtillon], ONERA-Université Paris Saclay (COmUE), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)

Subjects
Diffraction, Wavefront, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Computer science, FOS: Physical sciences, First light, Laser, 01 natural sciences, law.invention, 010309 optics, Optics, Laser guide star, Integral field spectrograph, law, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Pyramid (image processing), Astrophysics - Instrumentation and Methods for Astrophysics, business, Adaptive optics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics
Abstract

HARMONI is a visible and NIR integral field spectrograph, providing the E-ELT's core spectroscopic capability at first light. HARMONI will work at the diffraction limit of the E-ELT, thanks to a Classical and a Laser Tomographic AO system. In this paper, we present the system choices that have been made for these SCAO and LTAO modules. In particular, we describe the strategy developed for the different Wave-Front Sensors: pyramid for SCAO, the LGSWFS concept, the NGSWFS path, and the truth sensor capabilities. We present first potential implementations. And we asses the first system performance., Comment: SPIE proceeding, 2016

Published
2016
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4. ZELDA, a Zernike wavefront sensor for the fine measurement of quasi-static aberrations in coronagraphic systems: concept studies and results with VLT/SPHERE

Author

N'Diaye, M., Vigan, Arthur, Dohlen, K., Sauvage, J.-F., Caillat, A., Costille, A., Girard, J. H. V., Beuzit, J.-L., Fusco, T., Blanchard, P., Le merrer, J., Le Mignant, D., Madec, F., Moreaux, G., Mouillet, D., Puget, P., Zins, G., Marchetti, Enrico, Close, Laird, Véran, Jean-Pierre, Space Telescope Science Institute (STSci), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Chimie, Ingénierie Moléculaire et Matériaux d'Angers (CIMMA), Université d'Angers (UA)-Centre National de la Recherche Scientifique (CNRS), NRC Herzberg Institute of Astrophysics, and National Research Council of Canada (NRC)

Subjects
Physics, Wavefront, Zernike polynomials, business.industry, Brown dwarf, Astrophysics::Instrumentation and Methods for Astrophysics, Wavefront sensor, 01 natural sciences, Exoplanet, Deformable mirror, 010309 optics, symbols.namesake, Optics, Planet, 0103 physical sciences, symbols, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, business, Adaptive optics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

International audience; The high-contrast imaging instruments VLT/SPHERE and GPI have been routinely observing gas giant planets, brown dwarfs, and debris disks around nearby stars since 2013-2014. In these facilities, low-wind effects or differential aberrations between the extreme Adaptive Optics sensing path and the science path represent critical limitations for the observation of exoplanets orbiting their host star with a contrast ratio larger than 106 at small separations. To circumvent this problem, we proposed ZELDA, a Zernike wavefront sensor to measure these quasistatic aberrations at a nanometric level. A prototype was installed on VLT/SPHERE during its integration in Chile. We recently performed measurements on an internal source with ZELDA in the presence of Zernike or Fourier modes introduced with the deformable mirror of the instrument. In this communication, we present the results of our experiment and report on the contrast gain obtained with a first ZELDA-based wavefront correction. We finally discuss the suitability of such a solution for a possible upgrade of VLT/SPHERE and for its use with future E-ELT instruments or space missions with high-contrast capabilities (e.g. WFIRST-AFTA, HDST).

Published
2016
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5. SAXO, the SPHERE extreme AO system: on-sky final performance and future improvements

Author

Fusco, T., Sauvage, J.-F., Mouillet, D., Costille, A., Petit, C., Beuzit, J.-L., Dohlen, K., Milli, J., Girard, J., Kasper, M., Vigan, Arthur, Suarez, M., Soenke, C., Downing, M., N'Diaye, M., Baudoz, P., Sevin, A., Baruffolo, A., Schmid, H.-M., Salasnich, B., Hugot, E., Hubin, N., Marchetti, Enrico, Close, Laird, Véran, Jean-Pierre, Schmid, M., Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Technologie de Belfort-Montbeliard (UTBM), ESO, Physics Department [Garching], Technical University of Munich (TUM)-Technical University of Munich (TUM), Space Telescope Science Institute (STSci), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), NRC Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), ITA, USA, FRA, DEU, CHE, Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM)-Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées

Subjects
High Contrast Imaging, media_common.quotation_subject, Polarimetry, 01 natural sciences, 7. Clean energy, law.invention, 010309 optics, Telescope, Optics, law, 0103 physical sciences, Adaptive optics, 010303 astronomy & astrophysics, Coronagraph, Instrumentation: Adaptive Optics, media_common, Wavefront, Scientific instrument, Physics, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Exoplanet, 13. Climate action, Sky, Astrophysics::Earth and Planetary Astrophysics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument aims at detecting extremely faint sources (giant extrasolar planets) in the vicinity of bright stars1. Such a challenging goal requires the use of a very-high-order performance Adaptive Optics [AO] system feeding the scientific instruments with a quasi-perfect flat wave front corrected from all the atmospheric turbulence and internal defects. This AO system, called SAXO (Sphere Ao for eXoplanet Observation) is the heart of the instrument, a heart beating 1200 time per second and providing unprecedented image quality for a large ground based telescope at optical/near infrared wavelength. We will present the latest results obtained on-sky, demonstrating its exceptional performance (in terms of correction quality, stability and robustness) and tremendous potentiality for high contrast imaging and more specifically for exoplanet discovery.

Published
2016
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6. Estimating phase errors from pupil discontinuities from simulated on sky data: examples with VLT and Keck

Author

Lamb, Masen, Correia, Carlos, Sauvage, Jean-François, Véran, Jean-Pierre, Andersen, David, Vigan, Arthur, Wizinowich, Peter, Van Dam, Marcos, Mugnier, Laurent, Bond, Charlotte, Marchetti, Enrico, Close, Laird, ONERA - The French Aerospace Lab [Châtillon], ONERA-Université Paris Saclay (COmUE), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], NRC Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), Department of Public Administration, University at Albany [SUNY], State University of New York (SUNY)-State University of New York (SUNY), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), W.M. Keck Observatory, and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, business.industry, Zernike polynomials, media_common.quotation_subject, Astrophysics::Instrumentation and Methods for Astrophysics, Phase (waves), Sharpening, Classification of discontinuities, 01 natural sciences, 010309 optics, symbols.namesake, Cardinal point, Sky, 0103 physical sciences, symbols, Computer vision, Piston (optics), Astrophysics::Earth and Planetary Astrophysics, Artificial intelligence, business, Adaptive optics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, media_common
Abstract

International audience; We propose and apply two methods for estimating phase discontinuities for two realistic scenarios on VLT and Keck. The methods use both phase diversity and a form of image sharpening. For the case of VLT, we simulate the `low wind effect' (LWE) which is responsible for focal plane errors in low wind and good seeing conditions. We successfully estimate the LWE using both methods, and show that using both methods both independently and together yields promising results. We also show the use of single image phase diversity in the LWE estimation, and show that it too yields promising results. Finally, we simulate segmented piston effects on Keck/NIRC2 images and successfully recover the induced phase errors using single image phase diversity. We also show that on Keck we can estimate both the segmented piston errors and any Zernike modes affiliated with the non-common path.

Published
2016
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7. Characterisation of a turbulent module for the MITHIC high-contrast imaging testbed

Author

Vigan, Arthur, Postnikova, M., Caillat, A., Sauvage, J.-F., Dohlen, K., El Hadi, K., Fusco, T., Lamb, M., N'Diaye, M., Marchetti, Enrico, Close, Laird, Véran, Jean-Pierre, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Space Telescope Science Institute (STSci), NRC Herzberg Institute of Astrophysics, and National Research Council of Canada (NRC)

Subjects
Wavefront, Continuous phase modulation, business.industry, Zernike polynomials, Computer science, Testbed, Phase (waves), Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, 01 natural sciences, 010309 optics, symbols.namesake, Optics, 0103 physical sciences, symbols, Segmentation, business, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

Future high-contrast imagers on ground-based extremely large telescopes will have to deal with the segmentation of the primary mirrors. Residual phase errors coming from the phase steps at the edges of the segments will have to be minimized in order to reach the highest possible wavefront correction and thus the best contrast performance. To study these effects, we have developed the MITHIC high-contrast testbed, which is designed to test various strategies for wavefront sensing, including the Zernike sensor for Extremely accurate measurements of Low-level Differential Aberrations (ZELDA) and COronagraphic Focal-plane wave-Front Estimation for Exoplanet detection (COFFEE). We recently equipped the bench with a new atmospheric turbulence simulation module that offers both static phase patterns representing segmented primary mirrors and continuous phase strips representing atmospheric turbulence filtered by an AO or an XAO system. We present a characterisation of the module using different instruments and wavefront sensors, and the first coronagraphic measurements obtained on MITHIC., Comment: Presented at SPIE Astronomical Instrumentation + Telescope 2016

Published
2016
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8. Design optimization and lab demonstration of ZELDA: a Zernike sensor for near-coronagraph quasi-static measurements

Author

N'Diaye, Mamadou, Dohlen, Kjetil, Caillat, Amandine, Costille, Anne, Fusco, Thierry, Jolivet, Aïssa, Madec, Fabrice, Mugnier, Laurent, Paul, Baptiste, Sauvage, Jean-Francois, Soummer, Rémi, Vigan, Arthur, Wallace, J. K., Marchetti, Enrico, Close, Laird, Véran, Jean-Pierre, Space Telescope Science Institute (STSci), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), and National Research Council (Victoria, Canada)

Subjects
Physics, Dynamic range, business.industry, Zernike polynomials, Testbed, 01 natural sciences, Exoplanet, law.invention, 010309 optics, symbols.namesake, Optics, law, 0103 physical sciences, Calibration, symbols, Adaptive optics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Coronagraph, Quasistatic process
Abstract

International audience; The exoplanet direct imagers Gemini/GPI and VLT/SPHERE are built around extreme adaptive optics (ExAO) to correct the atmospheric turbulence and the aberrations associated with the optical surfaces. However, additional strategies are necessary to correct the non-common path aberrations (NCPA) between the ExAO and science paths that can limit the instrument contrast performance. To perform an adequate calibration, we have developed ZELDA, a Zernike sensor to achieve NCPA measurements with nanometric accuracy. We report the results of a new design analysis that maximizes the dynamic range, and from laboratory demonstrations on the LAM high-contrast testbed and on VLT/SPHERE during its integration.

Published
2014
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9. Studying Small Solar System Objects with Adaptive Optics in the Context of Space Missions

Author

Hartung, Markus, Coustenis, Athéna, Dumas, Christophe, Hirtzig, Mathieu, Herbst, T., Gendron, Éric, Close, Laird M., Lenzen, Rainer, Combes, Michel, Drossart, Pierre, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2006

10. Ground layer adaptive optics for the W. M. Keck Observatory: feasibility study

Author

Peter Wizinowich, Claire E. Max, Crystal L. Martin, Kyle B. Westfall, Olivier Lai, Kevin Bundy, D. Gavel, Charles C. Steidel, Jessica R. Lu, Lianqi Wang, Mark Chun, Richard Dekany, Tuan Do, M. Kassis, S. M. Ammons, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Schmidt, Dirk, Schreiber, Laura, Close, Laird M, W.M. Keck Observatory, Department of Physics and Astronomy [UCLA, Los Angeles], University of California [Los Angeles] (UCLA), University of California-University of California, California Institute of Technology (CALTECH), and Close, Laird M.

Subjects
W. M. Keck Observatory, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Image quality, Ground layer, FOS: Physical sciences, 01 natural sciences, law.invention, adaptive optics, 010309 optics, Telescope, Optics, law, Observatory, 0103 physical sciences, 14. Life underwater, Adaptive optics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, business.industry, ground layer, Exoplanet, Optical axis, Astrophysics - Instrumentation and Methods for Astrophysics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], astro-ph.IM
Abstract

Ground-layer adaptive optics (GLAO) systems offer the possibility of improving the "seeing" of large ground-based telescopes and increasing the efficiency and sensitivity of observations over a wide field-of-view. We explore the utility and feasibility of deploying a GLAO system at the W. M. Keck Observatory in order to feed existing and future multi-object spectrographs and wide-field imagers. We also briefly summarize science cases spanning exoplanets to high-redshift galaxy evolution that would benefit from a Keck GLAO system. Initial simulations indicate that a Keck GLAO system would deliver a 1.5x and 2x improvement in FWHM at optical (500 nm) and infrared (1.5 micron), respectively. The infrared instrument, MOSFIRE, is ideally suited for a Keck GLAO feed in that it has excellent image quality and is on the telescope's optical axis. However, it lacks an atmospheric dispersion compensator, which would limit the minimum usable slit size for long-exposure science cases. Similarly, while LRIS and DEIMOS may be able to accept a GLAO feed based on their internal image quality, they lack either an atmospheric dispersion compensator (DEIMOS) or flexure compensation (LRIS) to utilize narrower slits matched to the GLAO image quality. However, some science cases needing shorter exposures may still benefit from Keck GLAO and we will investigate the possibility of installing an ADC., Comment: 2018 Proceedings of the SPIE; published

Published
2018
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11. Phase A AO system design and performance for MOSAIC at the ELT

Author

Alastair Basden, Ariadna Calcines-Rosario, Ewan Fitzsimons, Eric Gendron, Kacem El Hadi, David Jenkins, Cornelis M. Dubbeldam, Matthew J. Townson, Simon L. Morris, Carine Morel, Gérard Rousset, Thierry Fusco, Kjetil Dohlen, Francois Hammer, Tim Morris, Pascal Vola, E. Younger, P. Jagourel, Centre for Advanced Instrumentation, Durham University (CfA), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ISIS Neutron and Muon Source (ISIS), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Close, Laird M., Schreiber, Laura, Schmidt, Dirk, Science and Technology Facilities Council (ISIS), Rutherford Appleton Laboratory, DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Durham University, and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
ADAPTIVE OPTICS, CALIBRATION, [PHYS]Physics [physics], Computer science, business.industry, Phase (waves), ERROR ANALYSIS, Mosaic (geodemography), 01 natural sciences, 010309 optics, [SPI]Engineering Sciences [physics], Optics, TOMOGRAPHY, 0103 physical sciences, Systems design, CONTROL SYSTEMS, business, 010303 astronomy & astrophysics, DEFORMABLE MIRRORS
Abstract

International audience; MOSAIC is a mixed-mode multiple object spectrograph planned for the ELT that uses a tiled focal plane to support a variety of observing modes. The MOSAIC AO system uses 4 LGS WFS and up to 4 NGS WFS positioned anywhere within the full 10 arcminute ELT field of view to control either the ELT M4/5 alone for GLAO operation feeding up to 200 targets in the focal plane, or M4/5 in conjunction with 10 open-loop DMs for MOAO correction. In this paper we present the overall design and performance of the MOSAIC GLAO and MOAO systems.

Published
2018
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12. Low wind effect on VLT/SPHERE: impact, mitigation strategy, and results

Author

Jean-François Sauvage, Arthur Vigan, Julien Milli, Konrad Tristam, Alexander Telle, Mamadou N'Diaye, Dimitri Mawet, David Mouillet, Zahed Wahhaj, Julien Girard, Cyril Pannetier, Claudia Reyes, Pierre Bourget, Thierry Fusco, Faustine Cantalloube, Jean-Luc Beuzit, Markus Kasper, European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Close, Laird M., Schreiber, Laura, and Schmidt, Dirk

Subjects
Wavefront, Radiative cooling, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Image quality, business.industry, Phase (waves), Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, 01 natural sciences, law.invention, 010309 optics, Telescope, Low emissivity, Cardinal point, Optics, 13. Climate action, law, 0103 physical sciences, Environmental science, Adaptive optics, business, Astrophysics - Instrumentation and Methods for Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

The low wind effect is a phenomenon disturbing the phase of the wavefront in the pupil of a large telescope obstructed by spiders, in the absence of wind. It can be explained by the radiative cooling of the spiders, creating air temperature inhomogeneities across the pupil. Because it is unseen by traditional adaptive optics (AO) systems, thus uncorrected, it significantly degrades the quality of AO-corrected images. We provide a statistical analysis of the strength of this effect as seen by VLT/SPHERE after 4 years of operations. We analyse its dependence upon the wind and temperature conditions. We describe the mitigation strategy implemented in 2017: a specific coating with low thermal emissivity in the mid-infrared was applied on the spiders of Unit Telescope 3. We quantify the improvement in terms of image quality, contrast and wave front error using both focal plane images and measured phase maps., Comment: 20 pages, 21 figures, SPIE 2018 conference proceeding

Published
2018
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13. Review of high-contrast imaging systems for current and future ground-based and space-based telescopes: Part II. Common path wavefront sensing/control and coherent differential imaging

Author

Kevin Fogarty, Eric Cady, Elsa Huby, Pierre Baudoz, Matthew A. Kenworthy, Laurent Pueyo, Michael Bottom, Mamadou N'Diaye, Brunella Carlomagno, Christoph U. Keller, Olivier Absil, Mathilde Beaulieu, Justin Knight, Michael J. Wilby, J. Kent Wallace, Garreth Ruane, Alexis Carlotti, A. J. Eldorado Riggs, Raphaël Galicher, Olivier Guyon, Nemanja Jovanovic, Kelsey Miller, Frans Snik, Emiel H. Por, Sebastiaan Y. Haffert, Marie Ygouf, Dan Sirbu, Johan Mazoyer, David S. Doelman, Jonas Kühn, Jeffrey Jewell, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Close, Laird M., Schreiber, Laura, and Schmidt, Dirk

Subjects
Wavefront, Computer science, 01 natural sciences, Exoplanet, Bridge (nautical), Field (computer science), law.invention, 010309 optics, law, 0103 physical sciences, Reflection (physics), Electronic engineering, Terrestrial planet, Instrumentation (computer programming), Differential (infinitesimal), Adaptive optics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Coronagraph, ComputingMilieux_MISCELLANEOUS
Abstract

The Optimal Optical Coronagraph (OOC) Workshop held at the Lorentz Center in September 2017 in Leiden, the Netherlands, gathered a diverse group of 25 researchers working on exoplanet instrumentation to stimulate the emergence and sharing of new ideas. In this second installment of a series of three papers summarizing the outcomes of the OOC workshop, we present an overview of common path wavefront sensing/control and Coherent Differential Imaging techniques, highlight the latest results, and expose their relative strengths and weaknesses. We layout critical milestones for the field with the aim of enhancing future ground/space based high contrast imaging platforms. Techniques like these will help to bridge the daunting contrast gap required to image a terrestrial planet in the zone where it can retain liquid water, in reflected light around a G type star from space.

Published
2018
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14. Kalman filter design for atmospheric tip/tilt, tip/tilt anisoplanatism and focus filtering on extremely large telescopes

Author

L. Gilles, Carlos Correia, Henri-François Raynaud, Caroline Kulcsár, Corinne Boyer, Brent Ellerbroek, Lianqi Wang, Thirty Meter Telescope Observatory Corp, Thirty Meter Telescope Observatory, Laboratoire Charles Fabry / Spim, Laboratoire Charles Fabry (LCF), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS), Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Marchetti, Enrico, Close, Laird M., and Véran, Jean-Pierre

Subjects
0209 industrial biotechnology, Computer science, business.industry, System identification, 02 engineering and technology, Filter (signal processing), Kalman filter, Linear-quadratic-Gaussian control, 01 natural sciences, [SPI.AUTO]Engineering Sciences [physics]/Automatic, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 010309 optics, 020901 industrial engineering & automation, Tilt (optics), Optics, Laser guide star, 0103 physical sciences, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Oversampling, Time domain, Focus (optics), business, Adaptive optics, ComputingMilieux_MISCELLANEOUS
Abstract

This paper discusses Kalman filter design to correct for atmospheric tip/tilt, tip/tilt anisoplanatism and focus disturbances in laser guide star multi-conjugate adaptive optics. Model identification, controller design and computation, command oversampling and disturbance rejection are discussed via time domain analysis and control performance evaluation. End-to-end high-fidelity sky-coverage simulations are presented by Wang and co-authors in a companion paper.

Published
2014
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15. Discretized aperture mapping with a micro-lenses array for interferometric direct imaging

Author

Enrico Giro, Julien Milli, Denis Mourard, Patrick Rabou, Jacopo Antichi, Marcel Carbillet, Julien Girard, Dimitri Mawet, Laurent Jolissaint, F. Patru, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Marchetti, Enrico, Close, Laird M., and Véran, Jean-Pierre

Subjects
Wavefront, Physics, Spatial filter, business.industry, Aperture, Astrophysics::Instrumentation and Methods for Astrophysics, Wavefront sensor, Image plane, 01 natural sciences, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 010309 optics, Entrance pupil, Optics, Aliasing, 0103 physical sciences, Nyquist frequency, business, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract

Discretized Aperture Mapping (DAM) appears as an original filtering tech nique easy to play with existing adaptive optics (AO) systems. In its essential DAM operates as an optical passive filter removing part of the phase residuals in the wavefront without introducing any difficult-to-align component in the Fourier conjugate of the entrance pupil plane. DAM reveals as a new interferometric technique combined with spatial filtering allowing direct imaging over a narrow field of view (FOV). In fact, the entrance pupil of a single telescope is divided into many sub-pupils so that the residual phase in each sub-pupil is filtered up to the DAM cut-off frequency. DAM enables to smooth the small scale wavefront defects which correspond to high spatial frequencies in the pupil plane and to low angular frequencies in the image plane. Close to the AO Nyquist frequency, such pupil plane spatial frequencies are not well measured by the wavefront sensor (WFS) due to aliasing. Once bigger than the AO Nyquist frequency, they are no more measured by the WFS due to the fitting limit responsible for the narrow AOFOV. The corresponding image plane angular frequencies are not tran smitted by DAM and are useless to image small FOVs, as stated by interferometry. That is why AO and DAM are complementary assuming that the DAM cut-off frequency is equal to the AO Nyquist frequency. Here we describe the imaging capabilities when DAM is placed downstream an AO system, over a convenient pupil which precedes the scientific detector. We show firstly that the imaging properties are preserved on a narrow FOV allowing direct imaging throughout interferometry. Then we show how the residual pupil plane spatial frequencies bigger than the AO Nyquist one are filtered out, as well as the residual halo in the image is dimmed.

Published
2014
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