High Resolution Optical Imaging Through the Atmosphere

High Resolution Optical Imaging Through the Atmosphere
Author: Robert W. Noyes
Publisher:
Total Pages: 57
Release: 1989
Genre: Astronomical instruments
ISBN:

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This program has concentrated on three major areas: the application of high angular resolution image reconstruction techniques to the reconstruction of solar surface features; speckle imaging of a wide range of astronomical sources; and the implementation of adaptive optics for faint object imaging. In this project, we have made substantial modifications to a technique for reconstruction of high resolution images from single short exposure solar frames, blind iterative deconvolution (IDC). We have been testing these improvements using numerical simulation data. Analysis of speckle data of the supernova SN1987A has detected a new bright source, 0.9 arcseconds south of the SN, as well as substantial structure in the region surrounding the SN. We also have new results on several Young Stellar Objects and supergiants. In the area of adaptive optics, an AOA wavefront sensor has been set up and tested using an image intensifier which increases its sensitivity by three orders of magnitude. Faint object image active tilt correction has also been tested with some important enhancements, including new highly linear and sensitive CCD quad cells developed by Cal Tech and Tektronix, and an off-the-shelf high speed 2-D tilting mirror with greatly improved specifications. The effects of only partially correcting atmospheric turbulence have been theoretically analyzed and numerically simulated.

Very High Angular Resolution Imaging

Very High Angular Resolution Imaging
Author: J.G. Robertson
Publisher: Springer Science & Business Media
Total Pages: 505
Release: 2013-12-01
Genre: Science
ISBN: 9401108803

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The 1990s are proving to be a very exciting p&iod for high angular resolution astronomy. At radio wavelengths a combination of new array instruments and pow erful imaging algorithms have generated images of unprecedented resolution and quality. In the optical and infrared, the great technical difficulties associated with constructing separated-aperture interferometers have been largely overcome, and many new instruments are now operating or are being developed. As these pro grams start to produce observational results they will be able to draw extensively on the experience gained by the radio-interferometry community. Thus it seemed that the time was ripe for a meeting which would bring together workers from all wavelength ranges to discuss the details of the science and art of "Very High Angular Resolution Imaging" . While the main emphasis of Symposium No. 158 was on high resolution tech niques from the radio, mm-wave, infrared and optical bands, it also provided an opportunity for presentation of astronomical results from these techniques. As well as giving our colleagues from the Northern Hemisphere a break from midwinter, the location of the Symposium in Australia recognised the continuing development of astronomical interferometry in this country, especially the recent completion of the Australia Telescope radio array, and the progress toward com missioning of the Sydney University Stellar Interferometer. A number of the par ticipants visited these instruments during the post-symposium tour.

Development of a CCD Based Solar Speckle Imaging System

Development of a CCD Based Solar Speckle Imaging System
Author: Peter Nisenson
Publisher:
Total Pages: 27
Release: 1986
Genre:
ISBN:

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This report describes the program to develop software and hardware for the purpose of obtaining high angular resolution images of the solar surface. The program included the purchase of a Charge Coupled Devices imaging system; an extensive laboratory and remote site testing of the camera system; the development of a software package for speckle image reconstruction which was eventually installed and tested at the Sacramento Peak Observatory; and experiments of the CCD system (coupled to an image intensifier) for low light level, narrow spectral band solar imaging.

Astronomy at High Angular Resolution

Astronomy at High Angular Resolution
Author: Henri M. J. Boffin
Publisher: Springer
Total Pages: 284
Release: 2016-08-24
Genre: Science
ISBN: 3319397397

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This book offers an essential compendium of astronomical high-resolution techniques. Recent years have seen considerable developments in such techniques, which are critical to advances in many areas of astronomy. As reflected in the book, these techniques can be divided into direct methods, interferometry, and reconstruction methods, and can be applied to a huge variety of astrophysical systems, ranging from planets, single stars and binaries to active galactic nuclei, providing angular resolution in the micro- to tens of milliarcsecond scales. Written by experts in their fields, the chapters cover adaptive optics, aperture masking imaging, spectra disentangling, interferometry, lucky imaging, Roche tomography, imaging with interferometry, interferometry of AGN, AGN reverberation mapping, Doppler- and magnetic imaging of stellar surfaces, Doppler tomography, eclipse mapping, Stokes imaging, and stellar tomography. This book is intended to enable a next generation of astronomers to apply high-resolution techniques. It informs readers on how to achieve the best angular resolution in the visible and near-infrared regimes from diffraction-limited to micro-arcsecond scales.

Imaging at High Angular Resolution of Stellar Surfaces and Close Environment

Imaging at High Angular Resolution of Stellar Surfaces and Close Environment
Author: Nicolas Nardetto
Publisher: EDP Sciences
Total Pages: 158
Release: 2019-09-26
Genre: Science
ISBN: 2759823733

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Imaging at high angular resolution (HRA) is a ?ourishing discipline. High performance instruments like the spectro-polarimeter SPHERE at VLT/ESO has recently been implemented. A harvest of splendid results is continuously coming from interferometry with PIONIER, MATISSE, and now GRAVITY (all at VLTI/ESO), VEGA and JouFlu (CHARA), and at longer wavelengths with ALMA at VLTI/ESO and NOEMA/IRAM. The future is already underway with the very close launch of JWST/NASA, and the development of ELT at ESO. HRA provides a unique way to study regions of stellar formation, proto-planetary discs as well as the surfaces of stars and their environments. This volume offers lectures given by world experts in the ?eld during the EvrySchatzman School on Stellar Physics (EES 2017) held in Roscoff, France. The addressed topics include a course of introduction to optical/IR interferometry covering the history and basic principles, a course on diffraction-dominated observational astronomy, and a course presenting the principles and instrumentation of optical long baseline interferometry. This book will be a valuable reference for researchers and students in the coming years.

Diffraction-Limited Imaging with Very Large Telescopes

Diffraction-Limited Imaging with Very Large Telescopes
Author: D.M. Alloin
Publisher: Springer Science & Business Media
Total Pages: 444
Release: 2012-12-06
Genre: Science
ISBN: 9400923406

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A few years ago, a real break-through happened in observational astronomy: the un derstanding of the effect of atmospheric turbulence on the structure of stellar images, and of ways to overcome this dramatic degradation. This opened a route to diffraction-limited observations with large telescopes in the optical domain. Soon, the first applications of this new technique led to some outstanding astrophysical results, both at visible and infrared wavelengths. Yet, the potential of interferometric observations is not fully foreseeable as the first long-baseline arrays of large optical telescopes are being built or cOIIllnissioned right now. In this respect a comparison with the evolution of radio-astronomy is tempting. From a situation where, in spite of the construction of giant antennas, low angular resolution was prevailing, the introduction of long baseline and very long baseline interferometry and the rapid mastering of sophisticated image reconstruction techniques, have brought on a nearly routine basis high dynamic range images with milliarcseconds resolution. This, of course, has completely changed our views of the radio sky.

NASA Reference Publication

NASA Reference Publication
Author:
Publisher:
Total Pages: 824
Release: 1977
Genre: Astronautics
ISBN:

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Image Processing Instrumentation for Speckle Interferometry and Imaging

Image Processing Instrumentation for Speckle Interferometry and Imaging
Author: H. A. McAlister
Publisher:
Total Pages: 11
Release: 1984
Genre:
ISBN:

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This final technical report describes the rationale for the acquisition of computer hardware for assembling an interactive image processing facility to be used for on-going programs of high angular resolution speckle interferometry of astronomical objects. Speckle interferometry is a technique for obtaining diffraction limited spatial information of distant objects through the turbulent atmosphere while simultaneously permitting differential positional measurements of very high accuracy. This method is being applied at Georgia State University in a program whose scientific goal is the detection of planetary mass companions in binary star systems. Funding from the DoD-University Research Instrumentation Program has permitted the acquisition of a dedicated digital image processing system to optimize the reduction and analysis of these data. The system components include a VAX 11/750 computer serving as host machine to an International Imaging Systems Model 70/F image processor with a variety of peripherals. The system is fully operational and extensive software development is underway. (Author).