SLODAR: measuring optical turbulence altitude with a Shack–Hartmann wavefront sensor
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TLDR
In this article, the vertical distribution of atmospheric optical turbulence above large telescopes is determined from time-averaged spatial cross-correlations of local wavefront slopes for Shack-Hartmann observations of binary stars.Abstract:
This paper discusses the use of Shack–Hartmann wavefront sensors to determine the vertical distribution of atmospheric optical turbulence above large telescopes. It is demonstrated that the turbulence altitude profile can be recovered reliably from time-averaged spatial cross-correlations of the local wavefront slopes for Shack–Hartmann observations of binary stars. The method, which is referred to as SLODAR, is analogous to the well known SCIDAR scintillation profiling technique, and a calibration against contemporaneous SCIDAR observations is shown. Hardware requirements are simplified relative to the scintillation method, and the number of suitable target objects is larger. The implementation of a Shack–Hartmann based turbulence monitor for use at the William Herschel Telescope is described. The system will be used to optimize adaptive optical observations at the telescope and to characterize anisoplanatic variations of the corrected point spread function.read more
Citations
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Adaptive optics in the formation of optical beams and images
TL;DR: In this article, the authors review the development of adaptive optics as an effective tool that allows using controllable optical elements to eliminate irregular distortions that occur as light propagates in an inhomogeneous medium.
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Determination of the profile of atmospheric optical turbulence strength from SLODAR data
TL;DR: In this paper, the authors determine the theoretical response of a SLODAR system based on a Shack-Hartmann WFS to a thin turbulent layer at a given altitude, and also as a function of the spatial power spectral index of the optical phase aberrations.
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MOAO first on-sky demonstration with CANARY
Eric Gendron,Fabrice Vidal,M. Brangier,Tim Morris,Z. Hubert,Alastair Basden,Gérard Rousset,Richard M. Myers,Fanny Chemla,Andy Longmore,Timothy Butterley,Nigel Dipper,C. N. Dunlop,Deli Geng,Damien Gratadour,David Henry,Philippe Laporte,N. Looker,D. Perret,Arnaud Sevin,G. Talbot,E. Younger +21 more
TL;DR: In this article, a multi-object adaptive optics (MOAO) system was successfully demonstrated on-sky for the first time at the 4.2m William Herschel Telescope, Canary Islands, Spain, at the end of September 2010.
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Tomography approach for multi-object adaptive optics
TL;DR: In this article, the authors proposed a method to retrieve the tomographic reconstructor using the on-sky wavefront measurements from an MOAO instrument, which is also used to calibrate the registrations between the off-axis wavefront sensors and the deformable mirrors placed in the science optical paths.
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Stereo-SCIDAR: optical turbulence profiling with high sensitivity using a modified SCIDAR instrument
Harry Shepherd,James Osborn,Richard Wilson,Timothy Butterley,R. Avila,V. S. Dhillon,Tim Morris +6 more
TL;DR: In this article, a stereo-scintillation detection and ranging (SCIDAR) system was proposed to map the optical refractive index fluctuations, generated by the atmospheric turbulence, along the line of sight to the astronomical target.
References
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Journal ArticleDOI
Profiling of atmospheric turbulence strength and velocity using a generalised SCIDAR technique
TL;DR: In this article, the strength and veloc-ity of atmospheric optical turbulence using a generalised SCIDAR technique is outlined and demonstrated. This method allows the full turbulent prole to be characterised from the telescope pupil up to any desired altitude.
Journal ArticleDOI
New challenges for adaptive optics: extremely large telescopes
TL;DR: In this paper, the performance of an adaptive optics (AO) system on a 100m diameter ground-based telescope working in the visible range of the spectrum is computed using an analytical approach.
Journal ArticleDOI
Atmospheric turbulence and wind profiles monitoring with generalized scidar
TL;DR: In this paper, a method for simultaneous measurement of the vertical distribution of the optical turbulence strength and wind velocity in the Earth's atmosphere, based on an analysis of spatio-temporal correlations of stellar scintillation images obtained with generalized scidar, is presented.
Journal ArticleDOI
Characterization of adaptive optics point spread function for anisoplanatic imaging. Application to stellar field deconvolution
TL;DR: In this article, the point spread function (PSF) of an adaptive optics system evolves in the Field Of View (FOV) and this variation strongly limits the conventional deconvolution methods for the processing of wide FOV images.
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