Dr. Andrei Tokovinin Profile

Dr. Andrei Tokovinin

Associate Astronomer at Cerro Tololo Inter-American Observatory

SPIE Involvement:

Author

Publications (44)

Proceedings Article | 28 August 2024 Presentation

A comparative analysis of novel turbulence profiling instrumentation at Paranal Observatory

Ryan Griffiths, Lisa Bardou, Timothy Butterley, James Osborn, Richard Wilson, Edison Bustos, Andrei Tokovinin, Miska Le Louarn, Angel Otarola

Proceedings Volume 13097, 130972U (2024) https://doi.org/10.1117/12.3018432

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Proceedings Article | 18 July 2024 Presentation + Paper

On-sky performance of SAMOS: a DMD-based multiobject spectrograph and imager for the SOAR 4.1 meter telescope

John Piotrowski, Massimo Robberto, Stephen Smee, Robert Barkhouser, Megan Donahue, Mario Gennaro, Albert Harding, Stephen Hope, Dana Koeppe, Zoran Ninkov, Jeffrey Poston, Lyle Schwartz, Andrei Tokovinin

Proceedings Volume 13096, 130960S (2024) https://doi.org/10.1117/12.3020796

KEYWORDS: Equipment, Digital micromirror devices, Spectrographs, Spectral resolution, Telescopes, Imaging systems, Point spread functions, Micromirrors, Astronomical imaging

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SPIE Journal Paper | 22 March 2023 Open Access

Dome seeing analysis of the Anglo-Australian Telescope

Josephine Munro, Jonah Hansen, Tony Travouillon, Doris Grosse, Andrei Tokovinin

JATIS, Vol. 9, Issue 01, 017004, (March 2023) https://doi.org/10.1117/12.10.1117/1.JATIS.9.1.017004

KEYWORDS: Domes, Telescopes, Wind speed, Turbulence, Convection, Mirrors, Vibration, Equipment, Meteorology, Relative humidity

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Proceedings Article | 25 August 2022 Presentation + Paper

Results of the dome turbulence sensor at the Anglo-Australian Telescope

Josephine Munro, Jonah Hansen, Doris Grosse, Tony Travouillon, Andrei Tokovinin

Proceedings Volume 12186, 121860A (2022) https://doi.org/10.1117/12.2629702

KEYWORDS: Domes, Telescopes, Mirrors, Turbulence, Humidity, Convection, Meteorology, Sensors, Observatories, Environmental sensing

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Proceedings Article | 11 July 2018 Paper

SAMplus: adaptive optics at optical wavelengths for SOAR

Daniel Faes, Andrei Tokovinin, Tarcio Vieira, Alexandre Mello, Marcia Domingues, Denis Andrade, Bruno Quint, Jesulino dos Santos

Proceedings Volume 10703, 107033C (2018) https://doi.org/10.1117/12.2312205

KEYWORDS: Adaptive optics, Actuators, Turbulence, Cameras, Telescopes, Photons, Stars, Monte Carlo methods, Monochromatic aberrations, Ultraviolet radiation

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Proceedings Article | 6 July 2018 Presentation + Paper

Dome seeing monitor and its results for the 4m Blanco telescope

Edison Bustos, Andrei Tokovinin

Proceedings Volume 10700, 107000Q (2018) https://doi.org/10.1117/12.2309652

KEYWORDS: Telescopes, Domes, Mirrors, Space telescopes, Turbulence, Cameras, Charge-coupled devices, Atmospheric propagation, Optical turbulence, Adaptive optics

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Proceedings Article | 6 July 2018 Paper

New wavefront-sensing guiders for SOAR

Andrei Tokovinin, Nicole David, José Piracés, Rolando Cantarutti

Proceedings Volume 10702, 107022F (2018) https://doi.org/10.1117/12.2312082

KEYWORDS: Mirrors, Stars, Cameras, Telescopes, Sensors, Charge-coupled devices, Vignetting, Lenses, Mechanical engineering

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Proceedings Article | 9 August 2016 Paper

An ADC for the SAM on the SOAR Telescope

Roberto Tighe, Andrei Tokovinin, Patricio Schurter, Manuel Martínez, Rolando Cantarutti

Proceedings Volume 9908, 99083B (2016) https://doi.org/10.1117/12.2233681

KEYWORDS: Space telescopes, Telescopes, Stars, Prisms, Glasses, Motion controllers, Refraction, Atmospheric modeling, Zemax, Adaptive optics

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Proceedings Article | 9 August 2016 Paper

SAMOS: a versatile multi-object-spectrograph for the GLAO system SAM at SOAR

Massimo Robberto, Megan Donahue, Zoran Ninkov, Stephen Smee, Robert Barkhouser, Mario Gennaro, Andrei Tokovinin

Proceedings Volume 9908, 99088V (2016) https://doi.org/10.1117/12.2233094

KEYWORDS: Digital micromirror devices, Large Synoptic Survey Telescope, Mirrors, Telescopes, Spectrographs, Cameras, Spectroscopy, Charge-coupled devices, Space telescopes, Adaptive optics

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Proceedings Article | 4 August 2016 Paper

SRAO: the first southern robotic AO system

Nicholas Law, Carl Ziegler, Andrei Tokovinin

Proceedings Volume 9907, 99070K (2016) https://doi.org/10.1117/12.2234446

KEYWORDS: Adaptive optics, Robotics, Speckle, Imaging systems, Robotic systems, Telescopes, Stars, Cameras, Turbulence, Near infrared

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Proceedings Article | 27 July 2016 Paper

SRAO: optical design and the dual-knife-edge WFS

Carl Ziegler, Nicholas Law, Andrei Tokovinin

Proceedings Volume 9909, 99093Z (2016) https://doi.org/10.1117/12.2231297

KEYWORDS: Adaptive optics, Robotics, Imaging systems, Stars, Adaptive optics, Stars, Wavefront sensors, Robotics, Mirrors, Cameras, Telescopes, Beam splitters, Sensors

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Proceedings Article | 24 September 2012 Paper

Performance of the CHIRON high-resolution Echelle spectrograph

Christian Schwab, Julien Spronck, Andrei Tokovinin, Andrew Szymkowiak, Matthew Giguere, Debra Fischer

Proceedings Volume 8446, 84460B (2012) https://doi.org/10.1117/12.925108

KEYWORDS: Charge-coupled devices, Spectrographs, Sensors, Prisms, Neodymium, Telescopes, Point spread functions, Iodine cells, Stars, Mirrors

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Proceedings Article | 17 September 2012 Paper

Surface layer turbulence measurements on the LSST site El Peñon using microthermal sensors and the lunar scintillometer LuSci

J. Sebag, P. Zimmer, J. Turner, J. McGraw, V. Krabbendam, A. Tokovinin, Edison Bustos, M. Warner, O. Wiecha

Proceedings Volume 8444, 844469 (2012) https://doi.org/10.1117/12.927017

KEYWORDS: Sensors, Telescopes, Turbulence, Large Synoptic Survey Telescope, Stereolithography, Electroluminescence, Optical turbulence, Observatories, Data acquisition, Resistance

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Proceedings Article | 13 September 2012 Paper

Performance of the SOAR adaptive module with UV Rayleigh guide star

Andrei Tokovinin, Roberto Tighe, Patricio Schurter, Rolando Cantarutti, Nicole van der Bliek, Manuel Martinez, Eduardo Mondaca, Steven Heathcote

Proceedings Volume 8447, 84474H (2012) https://doi.org/10.1117/12.925705

KEYWORDS: Adaptive optics, Mirrors, Ultraviolet radiation, Telescopes, Stars, Turbulence, Rayleigh guide stars, Cameras, Point spread functions, Charge-coupled devices

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Proceedings Article | 7 August 2010 Paper

Monitoring of the atmospheric turbulence profiles for the ELTs adaptive optics systems specification

Aziz Ziad, Julien Borgnino, François Martin, Jérôme Maire, Dali-Ali Wassila, Amokrane Berdja, Jean-Baptiste Daban, Yan Fanteï-Caujolle, Marc Sarazin, Andreï Tokovinin

Proceedings Volume 7733, 77334J (2010) https://doi.org/10.1117/12.857259

KEYWORDS: Telescopes, Adaptive optics, Atmospheric turbulence, Observatories, Wavefronts, Atmospheric optics, Algorithms, Global system for mobile communications, Image processing, CCD cameras

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Proceedings Article | 7 August 2010 Paper

Surface layer characterization at Paranal Observatory

G. Lombardi, J. Melnick, R. Hinojosa Goñi, J. Navarrete, M. Sarazin, A. Berdja, A. Tokovinin, R. Wilson, J. Osborn, T. Butterley, H. Shepherd

Proceedings Volume 7733, 77334D (2010) https://doi.org/10.1117/12.856772

KEYWORDS: Turbulence, Stereolithography, Stars, Ultrasonics, Observatories, Telescopes, Temperature metrology, Image quality, Temperature sensors, Physics

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Proceedings Article | 5 August 2010 Paper

Where is the surface-layer turbulence?

Andrei Tokovinin

Proceedings Volume 7733, 77331N (2010) https://doi.org/10.1117/12.856409

KEYWORDS: Turbulence, Stereolithography, Telescopes, Adaptive optics, Scintillation, Observatories, Profiling, Lanthanum, Remote sensing, Image quality

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Proceedings Article | 29 July 2010 Paper

SAM sees the light

Andrei Tokovinin, Roberto Tighe, Patricio Schurter, Rolando Cantarutti, Nicole van der Bliek, Manuel Martinez, Eduardo Mondaca, Andrés Montané, Wolnays Naudy Cortés

Proceedings Volume 7736, 77363L (2010) https://doi.org/10.1117/12.856407

KEYWORDS: Telescopes, Adaptive optics, Mirrors, Stars, Ultraviolet radiation, Camera shutters, Point spread functions, Laser guide stars, Sensors, Space telescopes

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Proceedings Article | 20 July 2010 Paper

Design of the CHIRON high-resolution spectrometer at CTIO

Christian Schwab, Julien F. Spronck, Andrei Tokovinin, Debra Fischer

Proceedings Volume 7735, 77354G (2010) https://doi.org/10.1117/12.856709

KEYWORDS: Telescopes, Cameras, Spectroscopy, Mirrors, Spectrographs, Prisms, Computer aided design, Image quality, Sensors, Charge-coupled devices

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Proceedings Article | 28 July 2008 Paper

LuSci: a lunar scintillometer to study ground layer turbulence

Jayadev Rajagopal, A. Tokovinin, E. Bustos, J. Sebag

Proceedings Volume 7013, 70131P (2008) https://doi.org/10.1117/12.789042

KEYWORDS: Turbulence, Scintillation, Sensors, Data modeling, Adaptive optics, Interferometry, Error analysis, Instrument modeling, Wind measurement, Velocity measurements

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Proceedings Article | 14 July 2008 Paper

SAM: a facility GLAO instrument

Andrei Tokovinin, Roberto Tighe, Patricio Schurter, Rolando Cantarutti, Nicole van der Bliek, Manuel Martinez, Eduardo Mondaca, Andres Montane

Proceedings Volume 7015, 70154C (2008) https://doi.org/10.1117/12.788015

KEYWORDS: Telescopes, Space telescopes, Mirrors, Adaptive optics, Stars, Ultraviolet radiation, Charge-coupled devices, Prototyping, Collimation, Wavefront sensors

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Proceedings Article | 11 July 2008 Paper

Two campaigns to compare three turbulence profiling techniques at Las Campanas Observatory

Joanna Thomas-Osip, Edison Bustos, Michael Goodwin, Charles Jenkins, Andrew Lambert, Gabriel Prieto, Andrei Tokovinin

Proceedings Volume 7014, 70145I (2008) https://doi.org/10.1117/12.789957

KEYWORDS: Turbulence, Telescopes, Lanthanum, Observatories, Scintillation, Stars, Sensors, Profiling, Ranging, Convolution

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Proceedings Article | 10 July 2008 Paper

Performance and error budget of a GLAO system

Andrei Tokovinin

Proceedings Volume 7015, 701526 (2008) https://doi.org/10.1117/12.788028

KEYWORDS: Point spread functions, Adaptive optics, Error analysis, Telescopes, Turbulence, Optical transfer functions, Atmospheric optics, Servomechanisms, Observatories, Astronomy

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Proceedings Article | 10 July 2008 Paper

The Multi Aperture Scintillation Sensor (MASS) used in the site selection of the Thirty Meter Telescope (TMT)

S. Els, M. Schoeck, J. Seguel, W. Skidmore, D. Walker, A. Tokovinin, V. Kornilov, R. Riddle, T. Travouillon, E. Bustos, J. Vasquez, R. Blum, B. Gregory, P. Gillett

Proceedings Volume 7012, 701222 (2008) https://doi.org/10.1117/12.788954

KEYWORDS: Clouds, Turbulence, Sensors, Telescopes, Heat flux, Cameras, Astronomy, Aerosols, Scintillation, Thirty Meter Telescope

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Proceedings Article | 28 June 2006 Paper

Modeling a GLAO system for the Gemini Observatory

David Andersen, David Crampton, Kei Szeto, Simon Morris, Michael Lloyd-Hart, Richard Myers, Jeff Stoesz, Andrei Tokovinin, Tim Butterley, N. Mark Milton, Jean-Pierre Véran, Richard Wilson

Proceedings Volume 6272, 62725B (2006) https://doi.org/10.1117/12.672229

KEYWORDS: Point spread functions, Gemini Observatory, Atmospheric modeling, Turbulence, Actuators, Adaptive optics, Monte Carlo methods, Stars, Performance modeling, Image quality

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Proceedings Article | 28 June 2006 Paper

Optimization of center of gravity algorithms in a Shack-Hartmann sensor

T. Fusco, S. Thomas, M. Nicolle, A. Tokovinin, V. Michau, G. Rousset

Proceedings Volume 6272, 627219 (2006) https://doi.org/10.1117/12.670811

KEYWORDS: Adaptive optics, Sensors, Wavefront sensors, Diffraction, Turbulence, Atmospheric turbulence, Charge-coupled devices, Error analysis, Optimization (mathematics), Point spread functions

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Proceedings Article | 23 June 2006 Paper

Site testing Dome A, Antarctica

J. Lawrence, M. C. Ashley, M. Burton, X. Cui, J. Everett, B. Indermuehle, S. Kenyon, D. Luong-Van, A. Moore, J. W. Storey, A. Tokovinin, T. Travouillon, C. Pennypacker, L. Wang, D. York

Proceedings Volume 6267, 62671L (2006) https://doi.org/10.1117/12.670960

KEYWORDS: Domes, Observatories, Turbulence, Infrared radiation, Astronomy, Control systems, Sensors, Telecommunications, Atmospheric optics, Iridium

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Proceedings Article | 25 October 2004 Paper

Using 50-mm electrostatic membrane deformable mirror in astronomical adaptive optics

Andrei Tokovinin, Sandrine Thomas, Gleb Vdovin

Proceedings Volume 5490, (2004) https://doi.org/10.1117/12.550044

KEYWORDS: Adaptive optics, Electrodes, Telescopes, Actuators, Micromachined deformable membrane mirrors, Deformable mirrors, Mirrors, Space telescopes, Nonlinear control, Monochromatic aberrations

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Proceedings Article | 25 October 2004 Paper

Design of ground-layer turbulence compensation with a Rayleigh beacon

Andrei Tokovinin, Sandrine Thomas, Brooke Gregory, Nicole van der Bliek, Patricio Schurter, Rolando Cantarutti, Eduardo Mondaca

Proceedings Volume 5490, (2004) https://doi.org/10.1117/12.550053

KEYWORDS: Adaptive optics, Turbulence, Telescopes, Space telescopes, Charge-coupled devices, Imaging systems, Human-machine interfaces, Mirrors, Stars, Sensors

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Proceedings Article | 28 September 2004 Paper

The Thirty Meter Telescope site testing system

Warren Skidmore, Matthias Schock, Andrei Tokovinin, George Djorgovski, Alistair Walker, Robert Blum, Tony Travouillon, Juan Seguel, Edison Bustos, David Walker, Joselina Vasquez, Paul Gillett

Proceedings Volume 5489, (2004) https://doi.org/10.1117/12.549384

KEYWORDS: Telescopes, Turbulence, Calibration, Atmospheric optics, Atmospheric turbulence, Motion measurement, Data modeling, Scintillation, Telecommunications, Thirty Meter Telescope

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Proceedings Article | 28 September 2004 Paper

A robotic instrument for measuring high altitude atmospheric turbulence from Dome C, Antarctica

Jon Lawrence, Michael Ashley, Suze Kenyon, John Storey, Andrei Tokovinin, James Lloyd, Mark Swain

Proceedings Volume 5489, (2004) https://doi.org/10.1117/12.551017

KEYWORDS: Domes, Telescopes, Turbulence, Stars, Scintillation, Atmospheric turbulence, CCD cameras, Observatories, Mirrors, Space telescopes

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Proceedings Article | 7 July 2004 Paper

Ground layer sensing and compensation

Andrei Tokovinin

Proceedings Volume 5382, (2004) https://doi.org/10.1117/12.566207

KEYWORDS: Point spread functions, Turbulence, Telescopes, Actuators, Adaptive optics, Space telescopes, Large telescopes, Linear filtering, Spatial filters, Sodium

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Proceedings Article | 7 February 2003 Paper

MASS: a monitor of the vertical turbulence distribution

Victor Kornilov, Andrei Tokovinin, Olga Vozyakova, Andrei Zaitsev, Nicolai Shatsky, Serguei Potanin, Marc Sarazin

Proceedings Volume 4839, (2003) https://doi.org/10.1117/12.457982

KEYWORDS: Turbulence, Scintillation, Telescopes, Sensors, Stars, Reflector telescopes, Adaptive optics, Active optics, Mirrors, Data modeling

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Proceedings Article | 7 February 2003 Paper

Preliminary results of the 2001-2002 Gemini sodium monitoring campaign at Cerro Tololo, Chile

Celine d'Orgeville, Francois Rigaut, Maxime Boccas, Christopher Dainty, Enrique Figueroa, Ralf Flicker, Brooke Gregory, Laurent Michaille, John Quartel, Andrei Tokovinin, Gelys Trancho, Nicholas Wooder

Proceedings Volume 4839, (2003) https://doi.org/10.1117/12.457005

KEYWORDS: Sodium, Telescopes, Stars, Gemini Observatory, Adaptive optics, Observatories, Calibration, Laser guide stars, Charge-coupled devices, Atmospheric optics

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Proceedings Article | 7 February 2003 Paper

Visible-light AO system for the 4.2-m SOAR telescope

Andrei Tokovinin, Brooke Gregory, Hugo Schwarz, Valery Terebizh, Sandriane Thomas

Proceedings Volume 4839, (2003) https://doi.org/10.1117/12.457089

KEYWORDS: Adaptive optics, Telescopes, Turbulence, Lawrencium, Stars, Point spread functions, CCD cameras, Sensors, Mirrors, Space telescopes

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Proceedings Article | 30 January 2003 Paper

Site survey for the Giant Segmented Mirror Telescope

Alistair Walker, Robert Blum, Maxime Boccas, Edison Bustos, Hugo Schwarz, Nicholas Suntzeff, Andrei Tokovinin

Proceedings Volume 4840, (2003) https://doi.org/10.1117/12.459881

KEYWORDS: Telescopes, Clouds, Turbulence, Atmospheric modeling, Observatories, Astronomy, Gemini Observatory, Large telescopes, Remote sensing, Adaptive optics

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Proceedings Article | 17 November 2000 Paper

ELP-OA: measuring the wavefront tilt without a natural guide star

Matthias Schoeck, Jean-Paul Pique, Alain Petit, Patrick Chevrou, Vincent Michau, Gilbert Grynberg, Arnold Migus, Nancy Ageorges, Veronique Bellanger, Francois Biraben, Ruy Deron, Hayden Fews, Francoise-Claude Foy, Claudia Hoegemann, Markus Laubscher, Daniel Mueller, Celine d'Orgeville, Olivier Peillet, Mike Redfern, Renaud Foy, Patricia Segonds, Richard Soden, Michel Tallon, Eric Thiebaut, Andrei Tokovinin, Jerome Vaillant, Jean-Marc Weulersse

Proceedings Volume 4125, (2000) https://doi.org/10.1117/12.409304

KEYWORDS: Telescopes, Stars, Sodium, Wavefronts, Adaptive optics, Modulation, Laser guide stars, Oscillators, Astronomy, Chemical species

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Proceedings Article | 16 August 2000 Paper

Polychromatic guide star: feasibility study

Renaud Foy, Jean-Paul Pique, Alain Petit, Patrick Chevrou, Vincent Michau, Gilbert Grynberg, Arnold Migus, Nancy Ageorges, Veronique Bellanger, Francois Biraben, Ruy Deron, Hayden Fews, Francoise-Claude Foy, Claudia Hoegemann, Markus Laubscher, Daniel Mueller, Celine d'Orgeville, Olivier Peillet, Mike Redfern, Matthias Schoeck, Patricia Segonds, Richard Soden, Michel Tallon, Eric Thiebaut, Andrei Tokovinin, Jerome Vaillant, Jean-Marc Weulersse

Proceedings Volume 4065, (2000) https://doi.org/10.1117/12.407359

KEYWORDS: Telescopes, Sodium, Stars, Oscillators, Adaptive optics, Modulation, Wavefronts, Chemical species, Photons, Laser guide stars

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Adaptive optics at astronomical telescopes aims at correcting in real time the phase corrugations of incoming wavefronts caused by the turbulent atmosphere, as early proposed by Babcock. Measuring the phase errors requires a bright source located within the isoplanatic patch of the program source. The probability that such a reference source exists is a function of the wavelength, of the required image quality (Strehl ratio), of the turbulence optical properties, and of the direction of the observation. It turns out that the sky coverage is disastrously low in particular in the visible wavelength range where, unfortunately, the gain in spatial resolution brought by adaptive optics is the largest. Foy and Labeyrie have proposed to overcome this difficulty by creating an artificial point source in the sky in the direction of the observation relying on the backscattered light due to a laser beam. This laser guide star (hereinafter referred to as LGS) can be bright enough to allow us to accurately measure the wavefront phase errors, except for two modes which are the piston (not relevant in this case) and the tilt. Pilkington has emphasized that the round trip time of the laser beam to the mesosphere, where the LGS is most often formed, is significantly shorter than the typical tilt coherence time; then the inverse-return-of-light principle causes deflections of the outgoing and the ingoing beams to cancel. The apparent direction of the LGS is independent of the tilt. Therefore the tilt cannot be measured only from the LGS. Until now, the way to overcome this difficulty has been to use a natural guide star to sense the tilt. Although the tilt is sensed through the entire telescope pupil, one cannot use a faint source because $APEX 90% of the variance of the phase error is in the tilt. Therefore, correcting the tilt requires a higher accuracy of the measurements than for higher orders of the wavefront. Hence current adaptive optics devices coupled with a LGS face low sky coverage. Several methods have been proposed to get a partial sky coverage for the tilt. The only one providing us with a full sky coverage is the polychromatic LGS (hereafter referred to as PLGS). We present here a progress report of the R&D program Etoile Laser Polychromatique et Optique Adaptative (ELP-OA) carried out in France to develop the PLGS concept. After a short recall of the principles of the PLGS, we will review the goal of ELP-OA and the steps to get over to bring it into play. We finally shortly described the effort in Europe to develop the LGS.

Proceedings Article | 7 July 2000 Paper

New challenges for adaptive optics: the OWL 100-m telescope

Norbert Hubin, Miska Le Louarn, Marc Sarazin, Andrei Tokovinin, Elise Vernet-Viard

Proceedings Volume 4007, (2000) https://doi.org/10.1117/12.390315

KEYWORDS: Turbulence, Adaptive optics, Telescopes, Stars, Wavefronts, Galactic astronomy, Visible radiation, Wavefront sensors, Large telescopes, Laser guide stars

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Proceedings Article | 7 July 2000 Paper

Pendular seismometer for correcting telescope pointing errors

Andrei Tokovinin

Proceedings Volume 4007, (2000) https://doi.org/10.1117/12.390300

KEYWORDS: Telescopes, Space telescopes, Servomechanisms, Prototyping, Picosecond phenomena, Sensors, Observatories, Adaptive optics, Mirrors, Global system for mobile communications

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Proceedings Article | 7 July 2000 Paper

ELPOA: toward the tilt measurement from a polychromatic laser guide star

Proceedings Volume 4007, (2000) https://doi.org/10.1117/12.390401

KEYWORDS: Telescopes, Sodium, Oscillators, Adaptive optics, Modulation, Laser guide stars, Photons, Chemical species, Wavefronts, Atmospheric optics

Read Abstract +

Adaptive optics at astronomical telescopes aims at correcting in real time the phase corrugations of incoming wavefronts caused by the turbulent atmosphere, as early proposed by Babcock. Measuring the phase errors requires a bright source, which is located within the isoplanatic patch of the program source. The probability that such a reference source exists is a function of the wavelength of the observation, of the required image quality (Strehl ratio), of the turbulence optical properties, and of the direction of the observation. Several papers have addressed the problem of the sky coverage as a function of these parameters (see e.g.: Le Louarn et al). It turns out that the sky coverage is disastrously low in particular in the short (visible) wavelength range where, unfortunately, the gain in spatial resolution brought by adaptive optics is the largest. Foy and Labeyrie have proposed to overcome this difficulty by creating an artificial point source in the sky in the direction of the observation relying on the backscattered light due to a laser beam. This laser guide star (hereafter referred to as LGS) can be bright enough to allow us to accurately measure the wavefront phase errors, except for two modes which are the piston (which is not relevant in this case) and the tilt. Pilkington has emphasized that the round trip time of the laser beam to the mesosphere, where the LGS is most often formed, is significantly shorter than the typical tilt coherence time; then the inverse-return- of-light principle causes deflections of the outgoing and the ingoing beams to cancel. The apparent direction of the LGS is independent of the tilt. Therefore the tilt cannot be measured only from the LGS. Until now, the way to overcome this difficulty has been to use a natural guide star to sense the tilt. Although the tilt is sensed through the entire telescope pupil, one cannot use a faint source because approximately equals 90% of the variance of the phase error is in the tilt. Therefore, correcting the tilt requires a higher accuracy of the measurements than for higher orders of the wavefront. Hence current adaptive optics devices coupled with a LGS face low sky coverage. Several methods have been proposed to get a partial or total sky coverage for the tilt, such as the dual adaptive optics concept, the elongation perspective method, or the polychromatic LGS (hereafter referred to as PLGS). We present here a progress report of the R&D program Etoile Laser Polychromatique et Optique Adaptative (ELP-OA) carried out in France to develop the PLGS concept. After a short recall of the principles of the PLGS, we will review the goal of ELP-OA and the steps to get over to bring it into play.

Proceedings Article | 7 July 2000 Paper

Concept and performance of multiple laser guide stars for 8-m-class telescopes

Elise Vernet-Viard, Norbert Hubin, Miska Le Louarn, Bernard Delabre, Guy Monnet, Andrei Tokovinin

Proceedings Volume 4007, (2000) https://doi.org/10.1117/12.390328

KEYWORDS: Adaptive optics, Telescopes, Point spread functions, Stars, Mirrors, Solids, Laser guide stars, Deformable mirrors, K band, Turbulence

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Proceedings Article | 5 July 2000 Paper

Measurements of the wavefront outer scale at Paranal: influence of this parameter in interferometry

Rodolphe Conan, Aziz Ziad, Julien Borgnino, Francois Martin, Andrei Tokovinin

Proceedings Volume 4006, (2000) https://doi.org/10.1117/12.390176

KEYWORDS: Global system for mobile communications, Wavefronts, Telescopes, Sensors, Interferometers, Interferometry, Servomechanisms, Atmospheric modeling, Einsteinium, Astronomy

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Proceedings Article | 11 September 1998 Paper

Wavefront outer-scale monitoring at La Silla

Andrei Tokovinin, Aziz Ziad, Francois Martin, Remy Avila, Julien Borgnino, Rodolphe Conan, Marc Sarazin

Proceedings Volume 3353, (1998) https://doi.org/10.1117/12.321672

KEYWORDS: Wavefronts, Global system for mobile communications, Telescopes, Adaptive optics, Lanthanum, Wavefront sensors, Turbulence, Astronomy, Velocity measurements, Observatories

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Showing 5 of 44 publications

Conference Committee Involvement (3)

Adaptive Optics Systems IV

22 June 2014 | Montréal, Quebec, Canada

Adaptive Optics Systems III

1 July 2012 | Amsterdam, Netherlands

Adaptive Optics Systems II

27 June 2010 | San Diego, California, United States

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