Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Download Correlation Wavefront Sensing And Turbulence Profiling For Solar Adaptive Optics full books in PDF, epub, and Kindle. Read online Correlation Wavefront Sensing And Turbulence Profiling For Solar Adaptive Optics ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Author : Matthew James Townson
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (16 download)
Download or read book Correlation Wavefront Sensing and Turbulence Profiling for Solar Adaptive Optics written by Matthew James Townson and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Lianqi Wang
Publisher :
ISBN 13 : 9780549115649
Total Pages : 186 pages
Book Rating : 4.1/5 (156 download)
Download or read book Atmospheric Turbulence Profiling Using Multiple Adaptive Optics Wavefront Sensors written by Lianqi Wang and published by . This book was released on 2007 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Slope Detection And Ranging (SloDAR) method recovers atmospheric turbulence profiles from the time averaged spatial cross-correlation of the wavefront slopes measured by Shack Hartmann wavefront sensors. We carried out numerical simulations of the SloDAR method before our experimental data were available as an aid to understanding the method. These simulation results are presented in this dissertation. The Palomar Multi-Guide Star Unit (MGSU) was set up to test tomographic multiple guide star adaptive optics and provided an ideal test bed for SloDAR turbulence altitude profiling. In this dissertation we present the data reduction methods and SloDAR results from MGSU observations made in 2006. Wind profiling was also performed using delayed delayed wavefront cross-correlations along with SloDAR analysis. The wind profiling analysis is shown to improve the height resolution of SloDAR method and in addition gives the wind velocity of the turbulent layers.
Author : Elena Masciadri
Publisher : Imperial College Press
ISBN 13 : 1848164866
Total Pages : 415 pages
Book Rating : 4.8/5 (481 download)
Download or read book Optical Turbulence written by Elena Masciadri and published by Imperial College Press. This book was released on 2009 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book collects most of the talks and poster presentations presented at the Optical Turbulence OCo Astronomy meets Meteorology international conference held on 15OCo18 September, 2008 at Nymphes Bay, Alghero, Sardinia, Italy. The meeting aimed to deal with one of the major causes of wavefront perturbations limiting the astronomical high-angular-resolution observations from the ground. The uniqueness of this meeting has been the effort to attack this topic in a synergic and multidisciplinary approach promoting constructive discussions between the actors of this science OCo the astronomers, meteorologists, physicists of the atmosphere and the experts in adaptive optics and interferometry techniques whose main goal is to correct, in real-time, the wavefront perturbations induced by atmospheric turbulence to restore at the telescope foci the best available image quality. Sample Chapter(s). Chapter 1: Optical Turbulence in High Angular Resolution Techniques in Astronomy (494 KB). Contents: Optical Turbulence in High Angular Resolution Techniques in Astronomy (J M Beckers); Optical Turbulence Profiles at CTIO from a 12-Element Lunar Scintillometer (P Hickson et al.); High Resolution SLODAR Measurements on Mauna Kea (T Butterley et al.); How We Can Understand the Antarctic Atmospheric? (J W V Storey et al.); The Paranal Surface Layar (J Melnick et al.); Introduction to Data Assimilation in Meteorology (P Brousseau OC L Auger); The Mauna Kea Weather Center: A Case for Custom Seeing Forecasts (T Cherubini et al.); Dealing with Turbulence: MCAO Experience and Beyond (R Ragazzoni et al.); Future-Look Science Operations for the LBT (R F Green); Surface Layer SLODAR (J Osborn et al.); and other papers. Readership: Advanced undergraduates and graduate students, and physicists working in the field of astronomy.
Author : Elena Masciadri
Publisher : World Scientific
ISBN 13 : 1908978171
Total Pages : 415 pages
Book Rating : 4.9/5 (89 download)
Download or read book Optical Turbulence: Astronomy Meets Meteorology - Proceedings Of The Optical Turbulence Characterization For Astronomical Applications written by Elena Masciadri and published by World Scientific. This book was released on 2009-09-14 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book collects most of the talks and poster presentations presented at the 'Optical Turbulence — Astronomy meets Meteorology' international conference held on 15-18 September, 2008 at Nymphes Bay, Alghero, Sardinia, Italy. The meeting aimed to deal with one of the major causes of wavefront perturbations limiting the astronomical high-angular-resolution observations from the ground. The uniqueness of this meeting has been the effort to attack this topic in a synergic and multidisciplinary approach promoting constructive discussions between the actors of this science — the astronomers, meteorologists, physicists of the atmosphere and the experts in adaptive optics and interferometry techniques whose main goal is to correct, in real-time, the wavefront perturbations induced by atmospheric turbulence to restore at the telescope foci the best available image quality./a
Author : Vladimir Petrovich Lukin
Publisher : SPIE Press
ISBN 13 : 9780819443373
Total Pages : 222 pages
Book Rating : 4.4/5 (433 download)
Download or read book Adaptive Beaming and Imaging in the Turbulent Atmosphere written by Vladimir Petrovich Lukin and published by SPIE Press. This book was released on 2002 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the wide application of adaptive optical systems, an understanding of optical wave propagation in randomly inhomogeneous media has become essential, and several numerical models of individual AOS components and of efficient correction algorithms have been developed. This monograph contains detailed descriptions of the mathematical experiments that were designed and carried out during more than a decade's worth of research.
Author :
Publisher :
ISBN 13 :
Total Pages : 242 pages
Book Rating : 4.3/5 (91 download)
Download or read book Optics in Atmospheric Propagation and Adaptive Systems written by and published by . This book was released on 2002 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 69 pages
Book Rating : 4.:/5 (227 download)
Download or read book Sensing Refractive Turbulence Profiles Using Wave Front Slope Measurements from Two Reference Sources written by and published by . This book was released on 1991 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines a remote sensing technique for measuring the atmospheric structure constant as a function of altitude by performing spatial correlation or wavefront sensor measurements. Two point sources are used to irradiate two wavefront sensors in the aperture plane of an optical system. The geometric relationship between the sources and the sensors gives rise to crossed optical paths. At the point where the paths cross, the correlation value of the turbulence contributions will be at a peak. The correlation is shown to be mathematically related to the structure constant in terms of an integral of the structure constant multiplied by a path weighting function. It is shown that the path weighting function can be made to have the characteristics of a sampling function and the value of the structure constant can be directly inferred from the correlation measurement. The vertical resolution and signal-to-noise ratio are calculated for a sample case of two-layer turbulence.
Author : James Allan Louthain
Publisher :
ISBN 13 : 9781423566984
Total Pages : 99 pages
Book Rating : 4.5/5 (669 download)
Download or read book Atmospheric Turbulence Scintillation Effects on Wavefront Tilt Estimation written by James Allan Louthain and published by . This book was released on 1997-12-01 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new atmospheric turbulence screen generator is developed for use in performance calculations of adaptive optics systems valid over a wide range of atmospheric turbulence parameters. The screen generator accounts for diffraction effects caused by weak turbulence and incorporates the phase, amplitude, and cross statistics of the perturbed optical field. The wavefront's phase and amplitude perturbations are taken from the correlation functions developed by Lee and Harp and the cross correlation of the phase and amplitude derived in this thesis. The screen generator uses a modal representation to perform a Fourier series expansion of the wavefront phase and amplitude over a square area. The phase, amplitude, and cross power spectral densities determined from the correlation functions are used in the Fourier series expansion. The mean square value and the structure functions of the phase, amplitude, and cross terms are calculated to within 1% of the theoretical values in a Monte Carlo experiment using the screen generator. Monte Carlo experiments performed using the screen generator showed the amplitude perturbations can significantly reduce the accuracy of full-aperture tilt estimation using image centroid motion. However, since the amplitude perturbations affect the image centroid, the tilt estimate using the combined amplitude and phase screen allows for a higher Strehl ratio than using only the phase to estimate the correction.
Download or read book A CCD Based Curvature Wavefront Sensor for Adaptive Optics in Astronomy written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive Optics (AO) is a technique for compensating the distortions introduced by atmospheric turbulence in astronomical imaging. To measure the distortions a wavefront sensor is needed. There are a number of fundamentally different types of wavefront sensors, one of which is the curvature wavefront sensor. At the European Southern Observatory (ESO) in Garching, Germany, several adaptive optics systems using curvature wavefront sensors are being developed for the Very Large Telescope (VLT) and the VLT interferometer (VLTI). Curvature AO-systems have traditionally used avalanche photodiodes (APDs) as detectors due to strict requirements of very short integration times (200 microsec) and very low readout noise. Advances in charge-coupled device (CCD) technology motivated an investigation of the use of a specially designed CCD as the wavefront sensor detector in a 60-element curvature AO system. A CCD has never been used before as the wavefront sensor in a low light level curvature adaptive optics system. This thesis shows that a CCD can achieve nearly the same performance as APDs at a fraction of the cost and with reduced complexity for high order wavefront correction. Moreover the CCD has higher quantum efficiency and a greater dynamic range than APDs. A readout noise of less than 1.5 electrons at 4000 frames per second was achieved. A back-illuminated thinned version of this CCD can replace APDs as the best detector for high order curvature wavefront sensing. This thesis presents the concept, the design and the evaluation of the CCD. The first frontside devices were successfully evaluated and the performance of the detector was proven in a laboratory experiment.
Author : Ralph M. Markson
Publisher :
ISBN 13 :
Total Pages : 342 pages
Book Rating : 4.:/5 (227 download)
Download or read book Atmospheric Turbulence Measurements in Support of Adaptive Optics Technology written by Ralph M. Markson and published by . This book was released on 1989 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is concerned with the relation of meteorological conditions to parameters and processes that influence the optical propagation properties of the turbulent atmosphere. The approach is centered around the use of aircraft and surface based remote sensors to investigate the relationship of the refractive index structure function parameter, Cn-sq, to various meteorological variables and to generally evaluate the accuracy of measurements of Cn-sq by in situ and remote means. the relationship of the atmospheric turbulence profile to the synoptic context and the use of physical models to predict the profile using standard meteorological profile data was also investigated. The study features two modes of data acquisition: 1) continuous archiving of 1 hr average wind profiles and turbulence levels with VHF doppler radar profiles, and 2) high time resolution aircraft measurements in association with other measurements (ground based optical scintillometers, thermosondes, radar profilers, and doppler sodar profilers). In one case all of the surface based systems were assembled in an intensive campaign given the acronym EWAK. The atmospheric turbulence profiles and resultant optical propagation parameters have been found to be strongly influenced by synoptic conditions. In particular, the turbulence is substantially affected by the strength and location of jet stream. A very strong correlation between wind shear (which is maximum above and below the core of the jet) and pilot reports of turbulence was found. Richardson number gave a much weaker indication possibly because of the poorer quality of the vertical temperature gradient data. (JHD).
Author : Dennis Anthony Montera
Publisher :
ISBN 13 : 9781423574590
Total Pages : 104 pages
Book Rating : 4.5/5 (745 download)
Download or read book Linear and Non-Linear Preprocessing of Wavefront Sensor Slope Measurements for Improved Adaptive Optics Performance written by Dennis Anthony Montera and published by . This book was released on 1996-03-01 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: New methods for preprocessing wavefront sensor (WFS) slope measurements are presented. Methods are developed to improve the accuracy of WFS slope measurements, as well as estimating key atmospheric and system parameters from the slope signals. Both statistical and artificial neural network solutions are investigated. Also, new atmospheric models for generating slope and phase data with the proper spatial and temporal statistics are developed. The experiments in improving the accuracy of WFS slope measurements include reducing the WFS slope measurement error and compensating for adaptive optics system time delay through temporal slope prediction. The experiments in key parameter estimation include estimating the Fried coherence length, r0, the wind speed profile, the strengths of the atmospheric turbulence layers, and the WFS mean square slope estimation error. Results of the experiments are used to make generalized conclusions in several key areas: first, the types of useful information that can be extracted from the WFS slope measurements; second, a comparison of linear or non linear methods; and third, the possibility of methods that can be developed which operate over useful ranges of seeing conditions. Overall, we find that the WFS slope measurements do contain useful information which can be extracted through various techniques. Simple transformations (either by neural network or statistical solution) on slope measurements can yield significant improvements is system accuracy without major changes to the adaptive optics system.
Author : Toby D. Reeves
Publisher :
ISBN 13 : 9781423573487
Total Pages : 231 pages
Book Rating : 4.5/5 (734 download)
Download or read book Performance Analysis of a Hartman Wavefront Sensor Used for Sensing Atmospheric Turbulence Statistics written by Toby D. Reeves and published by . This book was released on 1996-12-01 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric turbulence parameters, such as Fried's coherence diameter, the outer scale of turbulence, and the turbulence power law, are related to the wavefront slope structure function (SSF). The SSF is defined as the second moment of the wavefront slope difference as a function of both time and position. Knowledge of the SSF allows turbulence parameters to be estimated. Hartmann wavefront sensor (H-WFS) slope measurements composed of both signal and noise, allow the SSF to be estimated by computing a mean square difference of H- WFS slope measurements. The quality of the SSF estimate is quantified by the signal-to-noise ratio (SNR) of the estimator. This thesis develops a theoretical SNR expression for the SSF estimator. This SNR is a function of H-WFS geometry, the number of temporal frames included in the estimate, the outer scale, power law, and temporal properties of the turbulence. Spatial slope correlations are incorporated. Temporal slope correlations are incorporated using Taylor's frozen flow hypothesis. Results are presented for various H-WFS configurations and atmospheric turbulence properties.
Author :
Publisher : World Scientific
ISBN 13 : 981464434X
Total Pages : 1556 pages
Book Rating : 4.8/5 (146 download)
Download or read book Wspc Handbook Of Astronomical Instrumentation, The (In 5 Volumes) written by and published by World Scientific. This book was released on 2021-05-07 with total page 1556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Review of Volume 4:'The Handbook can be a good reference for a higher-degree science student approaching the subject or for an expert in a similar field in astronomical instrumentation. The reader requiring an in-depth presentation of a specific topic will be guided by the rich reference lists included at the end of each chapter.'The ObservatoryOur goal is to produce a comprehensive handbook of the current state of the art of astronomical instrumentation with a forward view encompassing the next decade. The target audience is graduate students with an interest in astronomical instrumentation, as well as practitioners interested in learning about the state of the art in another wavelength band or field closely related to the one in which they currently work. We assume a working knowledge of the fundamental theory: optics, semiconductor physics, etc. The purpose of this handbook is to bring together some of the leading experts in the world to discuss the frontier of astronomical instrumentation across the electromagnetic spectrum and extending into multimessenger astronomy.
Author :
Publisher :
ISBN 13 :
Total Pages : 24 pages
Book Rating : 4.3/5 (121 download)
Download or read book The Solar Optical Telescope written by and published by . This book was released on 1984 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Robert Tyson
Publisher : Academic Press
ISBN 13 : 0323156592
Total Pages : 311 pages
Book Rating : 4.3/5 (231 download)
Download or read book Principles Of Adaptive Optics written by Robert Tyson and published by Academic Press. This book was released on 2012-12-02 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: Principles of Adaptive Optics covers the basic principles of optics, wavefront sensing, controls, and wavefront correction that encompass the specialized field called adaptive optics. This book is composed of eight chapters that summarize the fundamental technology developments and the basic understanding of the various disciplines used in adaptive optics. After briefly reviewing the history, background, and developments of adaptive optics, this book goes on discussing the many sources of phase aberrations addressed by adaptive optics systems, such as linear effects due to turbulence, optical manufacturing, and misalignments, as well as errors that result from nonlinear thermal effects and fluid properties. The subsequent chapter deals with the performance enhancing role of adaptive optics systems in various disturbances. Other chapters describe the wavefront sampling, sensing, and correction subsystems. The concluding chapters explore the fundamental principles behind the adaptive optics control system and present summary expressions to determine the basic system parameters of an adaptive optics atmospheric compensation system. Communication scientists and engineers will find this work invaluable.
Author : Robert Tyson
Publisher : CRC Press
ISBN 13 : 082474165X
Total Pages : 337 pages
Book Rating : 4.8/5 (247 download)
Download or read book Adaptive Optics Engineering Handbook written by Robert Tyson and published by CRC Press. This book was released on 1999-11-10 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook supplies analytical tools for the design and development of adaptive optics systems to enhance their ability to adjust for atmospheric turbulence, optical fabrication errors, thermally induced distortions, and laser device aberrations. It provides recommendations for selecting, testing and installing a wavefront compensation system.
Author :
Publisher :
ISBN 13 :
Total Pages : 456 pages
Book Rating : 4.:/5 (3 download)
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
