Download or read book Special Issue on Adaptive Optics Control for Ground Based Telescopes written by Caroline Kulcsár and published by . This book was released on 2011 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adaptive Optics for Astronomical Telescopes written by John W. Hardy and published by Oxford Optical and Imaging Sci. This book was released on 1998 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book by one of the leaders in adaptive optics covers the fundamental theory and then describes in detail how this technology can be applied to large ground-based telescopes to compensate for the effects of atmospheric turbulence. It includes information on basic adaptive optics components and technology, and has chapters devoted to atmospheric turbulence, optical image structure, laser beacons, and overall system design. The chapter on system design is particularly detailed and includes performance estimation and optimization. Combining a clear discussion of physical principles with numerous real-world examples, this book will be a valuable resource for all graduate students and researchers in astronomy and optics.

Download or read book Adaptive Optics in Astronomy written by François Roddier and published by Cambridge University Press. This book was released on 1999-06-17 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics is set to revolutionise the future of astronomy; this is the first book on the subject and is set to become the standard reference.

Download or read book Integrated Modeling of Telescopes written by Torben Andersen and published by Springer Science & Business Media. This book was released on 2011-06-23 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ground- or space-based telescopes are becoming increasingly more complex and construction budgets are typically in the billion dollar range. Facing costs of this magnitude, availability of engineering tools for prediction of performance and design optimization is imperative. Establishment of simulation models combining different technical disciplines such as Structural Dynamics, Control Engineering, Optics and Thermal Engineering is indispensable. Such models are normally called Integrated Models because they involve many different disciplines. The models will play an increasingly larger role for design of future interdisciplinary optical systems in space or on ground. The book concentrates on integrated modeling of optical and radio telescopes but the techniques presented will be applicable to a large variety of systems. Hence, the book will be of interest to optical and radio telescope designers, designers of spacecrafts that include optical systems, and to designers of various complex defense systems. The book may also find use as a textbook for undergraduate and graduate courses within the field. "Adaptive Optics" is an exciting and relatively new field, originally dedicated to correction for blurring when imaging through the atmosphere. Although this objective is still of high importance, the concept of Adaptive Optics has recently evolved further. Today, the objective is not only to correct for atmospheric turbulence effects but also for a range of static and dynamical telescope aberrations. The notion of adaptive optics has expanded to the field of "Wavefront Control", correcting for a variety of system aberrations. Wavefront control systems maintain form and position of optical elements with high precision under static and dynamical load. In many ways, such systems replace the steel structures of traditional optical systems, thereby providing much lighter systems with a performance not possible before. Integrated Modeling is the foremost tool for studies of Wavefront Control for telescopes and complex optics and is therefore now of high importance. Springer has recently published two books on telescopes, "Reflecting Telescope Optics" by R. Wilson, and "The Design and Construction of Large Optical Telescopes" by P. Bely. Noting that a new (and expensive) generation of Extremely Large Telescopes with apertures in the 30-100 m range is on the way, the present book on integrated modeling is a good match to the existing books and an appropriate specialization and continuation of some subjects dealt with in those books.

Download or read book Wavefront Control for Space Telescope Applications Using Adaptive Optics written by and published by . This book was released on 2007 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future long dwell high resolution imagery satellites and space telescopes will require very large flexible primary mirrors. These large mirrors face many challenges including optical surface imperfections, structural vibrations, and jitter. A flexible mirror can overcome some of these challenges by applying adaptive optics techniques to correct mirror deformations and aberrations to produce image quality data. This paper examines and develops control techniques to control a deformable mirror subjected to a disturbance. The experimental portion of the work uses discrete time proportional integral control with second order filters to control disturbances in a deformable mirror and correct aberrations in an adaptive optics system using laser light. Using an adaptive optics testbed containing two deformable mirrors, two fast steering mirrors, two wave front sensors, a position sensor, and a combination of lenses the system corrects a simulated dynamic disturbance induced in the deformable mirror. Experiments using the described testbed successfully demonstrate wavefront control methods, including a combined iterative feedback and gradient control technique. This control technique results in a three fold improvement in RMS wavefront error over the individual controllers correcting from a biased mirror position. Second order discrete time notch filters are also used to remove induced low frequency actuator and sensor noise at 0.8 Hz, 2 Hz and 5 Hz. Additionally a 2 Hz structural disturbance is simulated on a Micromachined Membrane Deformable Mirror and removed using discrete time notch filters combined with a modal iterative closed loop feedback controller, showing a 36 fold improvement in RMS wavefront error over the iterative closed loop feedback alone.

Download or read book Adaptive Optics written by Michael S. Tarov and published by Nova Publishers. This book was released on 2002 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics is a field which is coming into its own with new discoveries occurring almost daily both in astronomy and in applications of AO in applied fields. In an adaptive optics system, the output from a wavefront sensor is used to calculate corrections that actively remove distortions from an image. The applications of adaptive optics in vision science have received considerable impetus from the knowledge developed by astronomers about how to correct images using AO technology. It is expected that developments in adaptive optics will radically change the face of astronomy in the 21st century. These systems will largely overcome the main limitation of ground-based telescopes, namely the severe reduction in image quality caused by turbulence in the Earth's atmosphere. Intended for use at near infrared wavelengths, adaptive optics allow imaging and spectroscopy at the limit of resolution imposed by optical diffraction an advance in astronomer's ability to view the heavens unparalleled since the invention of the telescope. AO is now also entering clinical medicine in the field of ophthalmology and other related fields. This new book presents several hundred current abstracts in the field, each fully indexed, for ease of access and contains a CD ROM for further research.

Download or read book The Design and Construction of Large Optical Telescopes written by Pierre Bely and published by Springer Science & Business Media. This book was released on 2006-05-26 with total page 527 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is no dearth of books on telescope optics and, indeed, optics is clearly a keyelementinthedesignandconstructionoftelescopes.Butitisbynomeans the only important element. As telescopes become larger and more costly, other aspects such as structures, pointing, wavefront control, enclosures, and project management become just as critical. Although most of the technical knowledge required for all these ?elds is available in various specialized books, journal articles, and technical reports, they are not necessarily written with application to telescopes in mind. This bookisa?rstattemptatassemblinginasingletextthebasicastronomicaland engineering principles used in the design and construction of large telescopes. Itsaimistobroadlycoverallmajoraspectsofthe?eld,fromthefundamentals ofastronomicalobservationto optics, controlsystems,structural,mechanical, andthermalengineering,aswellasspecializedtopicssuchassiteselectionand program management. This subject is so vast that an in-depth treatment is obviously imprac- cal. Our intent is therefore only to provide a comprehensive introduction to the essential aspects of telescope design and construction. This book will not replace specialized scienti?c and technical texts. But we hope that it will be useful for astronomers, managers, and systems engineers who seek a basic understanding of the underlying principles of telescope making, and for s- cialists who wish to acquaint themselves with the fundamental requirements and approaches of their colleagues in other disciplines.

Download or read book Introduction to Adaptive Optics written by Robert K. Tyson and published by SPIE Press. This book was released on 2000 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics systems and components have achieved a level of sophistication and simplicity that goes beyond traditional applications in astronomy and the military and into developments in medicine, manufacturing, and communications. This book was written for those interested in the multidisciplinary technology and those who need a broad-brush explanation without wading through thousands of journal articles. It follows the structure of a one-day tutorial taught by the author, including humor and sidebars of historical material.

Download or read book Dynamic Reconstruction and Multivariable Control for Force Actuated Thin Facesheet Adaptive Optics written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-11-18 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Multiple Mirror Telescope (MMT) under development at the University of Arizona takes a new approach in adaptive optics placing a large (0.65 m) force-actuated, thin facesheet deformable mirror at the secondary of an astronomical telescope, thus reducing the effects of emissivity which are important in IR astronomy. However, The large size of the mirror and low stiffness actuators used drive the natural frequencies of the mirror down into the bandwidth of the atmospheric distortion. Conventional adaptive optics takes a quasi-static approach to controlling the, deformable mirror. However, flexibility within the control bandwidth calls for a new approach to adaptive optics. Dynamic influence functions are used to characterize the influence of each actuator on the surface of the deformable mirror. A linearized model of atmospheric distortion is combined with dynamic influence functions to produce a dynamic reconstructor. This dynamic reconstructor is recognized as an optimal control problem. Solving the optimal control problem for a system with hundreds of actuators and sensors is formidable. Exploiting the circularly symmetric geometry of the mirror, and a suitable model of atmospheric distortion, the control problem is divided into a number of smaller decoupled control problems using circulant matrix theory. A hierarchic control scheme which seeks to emulate the quasi-static control approach that is generally used in adaptive optics is compared to the proposed dynamic reconstruction technique. Although dynamic reconstruction requires somewhat more computational power to implement, it achieves better performance with less power usage, and is less sensitive than the hierarchic technique. Grocott, Simon C. O. and Miller, David W. Langley Research Center; Marshall Space Flight Center ADAPTIVE OPTICS; DEFORMABLE MIRRORS; TELESCOPES; DYNAMIC CONTROL; OPTIMAL CONTROL; ACTUATORS; ATMOSPHERIC MODELS; BANDWIDTH; DISTORTION; EMISSIVITY; FLEXIBILITY; INFRARED ASTRONOMY; MATRI...

Download or read book Astronomical Optics written by Daniel J. Schroeder and published by Elsevier. This book was released on 2012-12-02 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by a recognized expert in the field, this clearly presented, well-illustrated book provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic instruments used by astronomers of today. - Written by a recognized expert in the field - Provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic instruments used by astronomers of today

Download or read book High Resolution Imaging in Microscopy and Ophthalmology written by Josef F. Bille and published by Springer. This book was released on 2019-08-13 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book provides a comprehensive overview of the application of the newest laser and microscope/ophthalmoscope technology in the field of high resolution imaging in microscopy and ophthalmology. Starting by describing High-Resolution 3D Light Microscopy with STED and RESOLFT, the book goes on to cover retinal and anterior segment imaging and image-guided treatment and also discusses the development of adaptive optics in vision science and ophthalmology. Using an interdisciplinary approach, the reader will learn about the latest developments and most up to date technology in the field and how these translate to a medical setting. High Resolution Imaging in Microscopy and Ophthalmology – New Frontiers in Biomedical Optics has been written by leading experts in the field and offers insights on engineering, biology, and medicine, thus being a valuable addition for scientists, engineers, and clinicians with technical and medical interest who would like to understand the equipment, the applications and the medical/biological background. Lastly, this book is dedicated to the memory of Dr. Gerhard Zinser, co-founder of Heidelberg Engineering GmbH, a scientist, a husband, a brother, a colleague, and a friend.

Download or read book Distributed Control of a Retinal Imaging Adaptive Optics System written by Maurizio Ficocelli and published by . This book was released on 2008 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years a technique known as adaptive optics (AO), commonly used to correct the dynamic wavefront error caused by atmospheric turbulence in ground-based telescopes, has been studied as a means of correcting the dynamic wavefront error caused by aberrations in the human eye, allowing for higher resolution retinal images. In order to compensate for these dynamic aberrations, a compact AO system that tracks and compensates for these changes in real-time is needed. To realize such a system, improvements must be made in two key components, namely the control algorithms and the design of the wavefront corrector. The latter represents the main focus of this thesis. The control problem in adaptive optics systems is generalized to that of shape control for a flexible membrane representing a deformable membrane mirror used in the wavefront corrector. Due to the dynamic nature of the aberrations in the eye, the shape control problem addressed is the tracking of an unknown and time-varying shape for a distributed membrane (i.e., desired shape of the mirror). The proposed controller design approach relies on two steps. The first step is to construct a Q -parameterized set of stabilizing controllers for the system under consideration and to derive conditions on the Q parameter in the controller expression to achieve regulation. Since the desired shape of the mirror is unknown and time-varying, the second step is to derive an online tuning algorithm for the Q parameter in the expression for the parameterized stabilizing controller. The online tuning of the Q parameter allows the controller to converge to the controller needed to achieve regulation, hence compensating for the lack of information on the desired shape for the deformable mirror. Decoupling introduced in the closed loop system allows tuning to be performed using decentralized algorithms.

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.

Download or read book Vibration Control of Active Structures written by A. Preumont and published by Springer Science & Business Media. This book was released on 2002-02-28 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: My objective in writing this book was to cross the bridge between the structural dynamics and control communities, while providing an overview of the potential of SMART materials for sensing and actuating purposes in active vibration c- trol. I wanted to keep it relatively simple and focused on systems which worked. This resulted in the following: (i) I restricted the text to fundamental concepts and left aside most advanced ones (i.e. robust control) whose usefulness had not yet clearly been established for the application at hand. (ii) I promoted the use of collocated actuator/sensor pairs whose potential, I thought, was strongly underestimated by the control community. (iii) I emphasized control laws with guaranteed stability for active damping (the wide-ranging applications of the IFF are particularly impressive). (iv) I tried to explain why an accurate pred- tion of the transmission zeros (usually called anti-resonances by the structural dynamicists) is so important in evaluating the performance of a control system. (v) I emphasized the fact that the open-loop zeros are more difficult to predict than the poles, and that they could be strongly influenced by the model trun- tion (high frequency dynamics) or by local effects (such as membrane strains in piezoelectric shells), especially for nearly collocated distributed actuator/sensor pairs; this effect alone explains many disappointments in active control systems.

Download or read book Keck Adaptive Optics written by and published by . This book was released on 1996 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics on the Keck 10 meter telescope will provide an unprecedented level of capability in high resolution ground based astronomical imaging. The system is designed to provide near diffraction limited imaging performance with Strehl

Download or read book Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems written by Zhizheng Wu and published by Springer Science & Business Media. This book was released on 2012-10-22 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems presents a novel design of wavefront correctors based on magnetic fluid deformable mirrors (MFDM) as well as corresponding control algorithms. The presented wavefront correctors are characterized by their linear, dynamic response. Various mirror surface shape control algorithms are presented along with experimental evaluations of the performance of the resulting adaptive optics systems. Adaptive optics (AO) systems are used in various fields of application to enhance the performance of optical systems, such as imaging, laser, free space optical communication systems, etc. This book is intended for undergraduate and graduate students, professors, engineers, scientists and researchers working on the design of adaptive optics systems and their various emerging fields of application. Zhizheng Wu is an associate professor at Shanghai University, China. Azhar Iqbal is a research associate at the University of Toronto, Canada. Foued Ben Amara is an assistant professor at the University of Toronto, Canada.

Download or read book Adaptive Optics written by Pierre Léna and published by . This book was released on 2009 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Until the 1970s, atmospheric seeing was considered as an absolute limitation for angular resolution of ground-based optical telescopes, exactly at the time of the conception of the new generation of giant optical telescopes, as the VLT and the Keck. Emerging in the context of the cold war with many constraints due to the research being classified, but with the new possibilities of digital control, astronomical adaptive optics was shown to be feasible in 1989 and gradually convinced an initially skeptical astronomical community of its potential. Twenty years later, it is a mandatory ingredient for the planning of Extremely Large Telescopes on the surface of the Earth, and has allowed many discoveries concerning galactic and extragalactic objects. Some directions for new developments are discussed.