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The performance of tomographic adaptive optics systems is intrinsically linked to the vertical profile of optical turbulence. Firstly, a sufficient number of discrete turbulent layers must be reconstructed to model the true continuous…

Instrumentation and Methods for Astrophysics · Physics 2020-04-08 O. J. D. Farley , J. Osborn , T. Morris , T. Fusco , B. Neichel , C. Correia , R. W. Wilson

Knowledge of the optical turbulence profile is important in adaptive optics (AO) systems, particularly tomographic AO systems such as those to be employed by the next generation of 40 m class extremely large telescopes (ELTs). Site…

Instrumentation and Methods for Astrophysics · Physics 2018-09-26 O. J. D. Farley , J. Osborn , T. Morris , M. Sarazin , T. Butterley , M. J. Townson , P. Jia , R. W. Wilson

We present a simple method of extracting a small number of reference optical turbulence and wind profiles from a large dataset for single conjugate and extreme adaptive optics simulations. These reference profiles can be used in slow…

Instrumentation and Methods for Astrophysics · Physics 2022-10-18 O. J. D. Farley

As telescopes become larger, into the era of ~40 m Extremely Large Telescopes, the high- resolution vertical profile of the optical turbulence strength is critical for the validation, optimization and operation of optical systems. The…

Instrumentation and Methods for Astrophysics · Physics 2017-01-11 J. Osborn , T. Butterley , M. J. Townson , A. P. Reeves , T. J. Morris , R. W. Wilson

Advanced adaptive optics (AO) instruments on ground-based telescopes require accurate knowledge of the atmospheric turbulence strength as a function of altitude. This information assists point spread function reconstruction, AO temporal…

The next generation of adaptive optics (AO) systems will require tomographic reconstruction techniques to map the optical refractive index fluctuations, generated by the atmospheric turbulence, along the line of sight to the astronomical…

Instrumentation and Methods for Astrophysics · Physics 2014-01-07 H. W. Shepherd , J. Osborn , R. W. Wilson , T. Butterley , R. Avila , V. S. Dhillon , T. J. Morris

Knowledge of the Earth's atmospheric optical turbulence is critical for astronomical instrumentation. Not only does it enable performance verification and optimisation of existing systems but it is required for the design of future…

Instrumentation and Methods for Astrophysics · Physics 2018-06-13 J. Osborn , R. W. Wilson , M. Sarazin , T. Butterley , A. Chacón , F. Derie , O. J. D. Farley , X. Haubois , D. Laidlaw , M. LeLouarn , E. Masciadri , J. Milli , J. Navarrete , M. J. Townson

Monitoring turbulence parameters is crucial in high-angular resolution astronomy for various purposes, such as optimising adaptive optics systems or fringe trackers. The former are present at most modern observatories and will remain…

Instrumentation and Methods for Astrophysics · Physics 2023-10-25 Nuno Morujão , Carlos Correia , Paulo Andrade , Julien Woillez , Paulo Garcia

In addition to astro-meteorological parameters, such as seeing, coherence time and isoplanatic angle, the vertical profile of the Earth's atmospheric turbulence strength and velocity is important for instrument design, performance…

Instrumentation and Methods for Astrophysics · Physics 2018-09-24 James Osborn , Marc Sarazin

The strength and vertical distribution of atmospheric turbulence is a key factor determining the performance of optical and infrared telescopes, with and without adaptive optics. Yet, this remains challenging to measure. We describe a new…

Instrumentation and Methods for Astrophysics · Physics 2019-10-11 Paul Hickson , Bin Ma , Zhaohui Shang , Suijian Xue

Adaptive optics (AO) is a technology in modern ground-based optical telescopes to compensate the wavefront distortions caused by atmospheric turbulence. One method that allows to retrieve information about the atmosphere from telescope data…

Instrumentation and Methods for Astrophysics · Physics 2018-04-04 Tapio Helin , Stefan Kindermann , Jonatan Lehtonen , Ronny Ramlau

With the prospect of the next generation of ground-based telescopes, the extremely large telescopes (ELTs), increasingly complex and demanding adaptive optics (AO) systems are needed. This is to compensate for image distortion caused by…

Instrumentation and Methods for Astrophysics · Physics 2017-01-31 L. Catala , A. Ziad , Y. Fantei-Caujolle , S. M. Crawford , D. A. H. Buckley , J. Borgnino , F. Blary , M. Nickola , T. Pickering

Current projects for large telescopes demand a proper knowledge of atmospheric turbulence to design efficient adaptive optics systems in order to reach large Strehl ratios. However, the proper characterization of the turbulence above a…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 B. Garcia-Lorenzo , A. Eff-Darwich , J. J. Fuensalida , J. Castro-Almazan

Atmospheric optical turbulence seriously limits the performance of high angular resolution instruments. An 8-night campaign of measurements was carried out at the LAMOST site in 2011, to characterize the optical turbulence. Two instruments…

Instrumentation and Methods for Astrophysics · Physics 2015-05-21 L. -Y. Liu , C. Giordano , Y. -Q. Yao , J. Vernin , M. Chadid , H. -S. Wang , J. Yin , Y. -P. Wang

The search for Earth-like exoplanets requires high-contrast and high-angular resolution instruments, which designs can be very complex: they need an adaptive optics system to compensate for the effect of the atmospheric turbulence on image…

Instrumentation and Methods for Astrophysics · Physics 2020-12-16 Lucie Leboulleux , Raphaël Galicher , Eric Gendron , Pierre Baudoz , Gérard Rousset

Seeing-limited resolution in large telescopes working over wide wavelength range depends substantially on the turbulence outer scale and cannot be adequately described by one "seeing" value. We attempt to clarify frequent confusions on this…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 P. Martinez , J. Kolb , A. Tokovinin , M. Sarazin

The efficiency of the management of top-class ground-based astronomical facilities supported by Adaptive Optics (AO) relies on our ability to forecast the optical turbulence (OT) and a set of relevant atmospheric parameters. Indeed, in…

Instrumentation and Methods for Astrophysics · Physics 2020-06-14 E. Masciadri , G. Martelloni , A. Turchi

We design an optical feedback network making use of machine learning techniques and demonstrate via simulations its ability to correct for the effects of turbulent propagation on optical modes. This artificial neural network scheme only…

Signal Processing · Electrical Eng. & Systems 2018-06-22 Sanjaya Lohani , Ryan T. Glasser

We discuss several improvements in the detection of atmospheric turbulence using SLOpe Detection And Ranging (SLODAR). Frequently, SLODAR observations have shown strong ground-layer turbulence, which is beneficial to adaptive optics. We…

Astrophysics · Physics 2009-11-13 Michael Goodwin , Charles Jenkins , Andrew Lambert

Nullifying the servo bandwidth errors improves the strehl ratio by a substantial quantity in adaptive optics systems. An effective method for predicting atmospheric turbulence to reduce servo bandwidth errors in real time closed loop…

Instrumentation and Methods for Astrophysics · Physics 2011-09-14 Akondi Vyas , M B Roopashree , B Raghavendra Prasad
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