Results 41 to 50 of about 403,575 (349)

A Real-Time Measurement System for Atmospheric Turbulence Intensity and Distribution Based on the GLAO System

open access: yesApplied Sciences, 2023
Measuring the intensity and distribution of atmospheric optical turbulence at large-aperture astronomical telescope sites is crucial to optimizing turbulence correction for different layers.
Xian Ran   +7 more
doaj   +1 more source

A case of Beauveria bassiana keratitis confirmed by internal transcribed spacer and LSU rDNA D1–D2 sequencing

open access: yesNew Microbes and New Infections, EarlyView., 2014
Abstract We describe a case of fungal keratitis due to Beauveria bassiana in a farmer with Fuchs' dystrophy, treated with amphotericin B. Surgery with penetrating keratoplasty was necessary to resolve the lesions. Susceptibility testing and molecular sequencing permitted the identification and treatment of this rare aetiological agent of invasive ...
M. Ligozzi   +8 more
wiley   +1 more source

On-sky wide field adaptive optics correction using multiple laser guide stars at the MMT [PDF]

open access: yes, 2008
We describe results from the first astronomical adaptive optics system to use multiple laser guide stars, located at the 6.5-m MMT telescope in Arizona. Its initial operational mode, ground-layer adaptive optics (GLAO), provides uniform stellar wavefront
Baranec   +40 more
core   +2 more sources

Quaternary adaptive optics

open access: yesOptics Express, 2019
We present a new Point Diffraction Interferometer (PDI). Binary adaptive optics (BAO) and Quaternary Adaptive Optics (QAO) can be performed with the help of this PDI as a wavefront sensor. The PDI interferogram, once binarized, is used in two consecutive steps to produce a quaternary mask with phase values 0, π/2, π and 3π/2.
Manuel P. Cagigal   +5 more
openaire   +3 more sources

The Durham adaptive optics real-time controller: Capability and ELT suitability [PDF]

open access: yes, 2012
The Durham adaptive optics real-time controller is a generic, high performance real-time control system for astronomical adaptive optics systems. It has recently had new features added as well as performance improvements, and here we give details of these, as well as ways in which optimisations can be made for specific adaptive optics systems and ...
arxiv   +1 more source

Design and Experimental Validation of a Model-Free Controller for Beam Stabilization in Adaptive Optics Systems

open access: yesIEEE Photonics Journal
Stabilization of optical beams has always been a key factor affecting the performance of many optical systems. The Adaptive optics (AO) beam stabilization system requires further development to cope with increasingly complex application scenarios and ...
Sicheng Guo   +6 more
doaj   +1 more source

Fast Restoration of Aberration-Degraded Extended Object Based on Local Region Abstraction

open access: yesIEEE Photonics Journal, 2018
The compensating capability of wavefront sensorless adaptive optics (WFSless AO) system for extended object images degraded by aberration is severely limited to correction speed due to largely sized images and low frame rate of camera.
Lianghua Wen   +8 more
doaj   +1 more source

The Extreme Learning Machine for the Extraction of Mono-Exponential Decay Time

open access: yesIEEE Photonics Journal, 2023
The mono-exponential decay has been used to describe various physical phenomena such as cavity ring-down signal, fluorescence decay, etc. In this paper, a neural network method of extreme learning machine (ELM) is adopted to efficiently extract decay ...
Xing He   +4 more
doaj   +1 more source

Visible near-diffraction limited lucky imaging with full-sky laser assisted adaptive optics [PDF]

open access: yes, 2014
Both lucky imaging techniques and adaptive optics require natural guide stars, limiting sky coverage, even when laser guide stars are used. Lucky imaging techniques become less successful on larger telescopes unless adaptive optics is used, as the fraction of images obtained with well behaved turbulence across the whole telescope pupil becomes ...
arxiv   +1 more source

Adaptive Optics Correction of the Wavefront Distortions Induced by Segments Misalignment in Extremely Large Telescope [PDF]

open access: yes, 2006
The capability of the adaptive optics to correct for the segmentation error is analyzed in terms of the residual wavefront RMS and the power spectral density of the phase.
Verinaud, Christophe, Yaitskova, Natalia
core   +2 more sources

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