Developments In Astrometry And Their Impact On Astrophysics And Geodynamics
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Developments In Astrometry And Their Impact On Astrophysics And Geodynamics
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Author : Ivan I. Mueller
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-12-01
Developments In Astrometry And Their Impact On Astrophysics And Geodynamics written by Ivan I. Mueller and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-12-01 with Science categories.
In this review talk, I would like to report on the proper motion analysis, which has been recently carried out together with M. Soma and M. Yoshizawa: There has been a persistent demand in astronomy for accurate stellar positions and proper motions, which are represented by an inertial reference system constructed on the basis of a set of consistent astronomical constants. In the reference system the precessional constant plays a primary role. In a series of papers Fricke (1967a,b, 1977a,b) has deter mined the luni-solar precessional correction to Newcomb's value and the fictitious motion of the equinox, which have been adopted in the "IAU (1976) System of Astronomical Con stants". Based on the precessional correction and the equinoctial motion thus established, the fundamental reference system, the FK5 system (Fricke et al. 1988) for positions and proper motions, has been constructed. However, for several years geodetic VLBI (McCarthy & Luzum 1991) and LLR (Williams et at. 1991) observations have been suggesting an additional correction to the luni-solar precessional constant of the IAU (1976) System. That is, these observations indicate the precessional correction of 6. p ~ -0:'30/cent to the FK5 system. But, the observational period ofthe earth orientation is considered to be still insufficient to separate unambiguously the precessional change of the earth orientation from the nutation with the longest period of 18. 6 years.
Astrometry For Astrophysics
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Author : William F. van Altena
language : en
Publisher: Cambridge University Press
Release Date : 2013
Astrometry For Astrophysics written by William F. van Altena and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Nature categories.
Unifying work by a broad range of experts in the field, this is the most complete textbook on observational astrometry.
Astronomical And Astrophysical Objectives Of Sub Milliarcsecond Optical Astrometry
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Author : Erik Høg
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-12-01
Astronomical And Astrophysical Objectives Of Sub Milliarcsecond Optical Astrometry written by Erik Høg and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-12-01 with Science categories.
Astrometry is on the threshold of great changes due to the fact that this decade, alone, is witnessing an improvement of stellar positions equivalent to the total improvement of the previous two centuries. The Hipparcos Satellite has concluded its observations, and the catalog is in preparation. Preliminary results assure that the Hipparcos catalog will provide positions, parallaxes and annual proper motions for over 100,000 stars with accuracies of 1.5 milliarcseconds. In addition, the Tycho catalog will provide positions of about 30 milliarcseconds accuracy for over 1 million stars, and annual proper motions with 3 milliarcsecond accuracy will subsequently be ob tained by means of first epoch positions from the Astrographic Catalog. Optical interferometers on the ground are beginning operation, and these instruments can provide observational accuracies of approximately one milliarcsecond. Also, the traditional reference frame based on the Fun damental Catalog of bright stars is being replaced by the extragalactic ref erence frame, based on radio sources with accuracies of one milliarcsecond. Thus, astrometry will change from a fundamental reference frame defined in terms of the dynamical reference frame of the solar system with accuracies of 100 milliarcseconds to a space-fixed, extragalactic reference frame with accuracies of one milliarcsecond. Future astrometric observations should be in the 1 -100 milliarcsecond accuracy range. There are a number of concepts for future astrometric instruments in space. Most of these can provide sub-milliarcsecond astrometric accuracies.
Galactic And Solar System Optical Astrometry
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Author : L. V. Morrison
language : en
Publisher: Cambridge University Press
Release Date : 1994-05-26
Galactic And Solar System Optical Astrometry written by L. V. Morrison and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994-05-26 with Science categories.
Astrometry - the study of the positions of astronomical objects and how they move across the sky - is a cornerstone of modern astronomy. Pinning down the distances to and motions of stars in our Galaxy is fundamental - it can lead to an understanding of the origin of these stars and how together they affect the evolution of our Galaxy. Similarly, measuring the motions of planets, their satellites and asteroids is crucial to unravelling the origin and evolution of our solar system (as well as to the planning of space missions to explore them). A workshop held jointly by the Royal Greenwich Observatory and the Institute of Astronomy, in Cambridge, offered an unusual opportunity to bring together astronomers from the fields of Galactic and solar system astrometry. Gathered in this volume are the articles they presented. Together, these provide an auspicious review of optical astrometry and our understanding of the evolution of the Galaxy and solar system for graduate students and researchers.
Transactions Of The International Astronomical Union
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Author : Immo Appenzeller
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Transactions Of The International Astronomical Union written by Immo Appenzeller and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.
IAU Transactions XXIIB summarizes the work of the XXIInd General Assembly. The discourses given during the Inaugural and Closing Ceremonies are reproduced in Chapters I and III, respectively. The proceedings of the two sessions of the General Assembly will be found in Chapter II, which includes the Resolutions and the report of the Finance Committee. The Statutes, Bye-Laws and a few working rules of the Union are published in Chapter IV. The Accounts and other aspects of the administration of the Union are recorded in Chapter V, together with the report of the Executive Committee for this last triennium, and provide the permanent record for the Union in the period 1991-1994. This volume also contains the Commission reports from The Hague compiled by the Presidents of the Commissions (Chapter VI). Finally, Chapter VII contains the list of countries adhering to the Union and the alphabetical, geographical and commission membership lists of about 8000 individual members. The IAU still appears to be unique among the scientific Unions in maintaining this category of individual membership which contributes in a crucial way to the spirit and the aims of the Union.
Cosmological Parameters And The Evolution Of The Universe
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Author : Katsuhiko Sato
language : en
Publisher: Springer Science & Business Media
Release Date : 1999-01-31
Cosmological Parameters And The Evolution Of The Universe written by Katsuhiko Sato and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999-01-31 with Science categories.
How old is our Universe? At what speed is our Universe expanding? Is our universe flat or curved? How is the hierarchical structure of the present Universe formed? The purpose of IAU Symposium 183 on the Cosmological Parameters and the Evolution of the Universe was to encourage a state-of-the-art discussion and assessment of cosmology by putting together the latest observational data and theoretical ideas on the evolution of the universe and cosmological parameters. In this volume, excellent reviews on these subjects by distinguished scientists are included. The first article by M.S. Longair, `Cosmological Parameters and the Evolution of the Universe: Progress and Prospect', is a magnificent general review which can be understood by non-specialists. The other reviews include Hubble Constants (W.L. Freedman, G.A. Tammann), Microwave Background Radiation (R.B. Partridge, N. Sugiyama), Galaxy Formation and Evolution (R.S. Ellis) and Alternative Cosmological Models (J.V. Narlikar). In addition to the reviews, recent observational and theoretical developments by outstanding active scientists are included.
Interferometry And Synthesis In Radio Astronomy
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Author : A. Richard Thompson
language : en
Publisher: Springer
Release Date : 2017-02-22
Interferometry And Synthesis In Radio Astronomy written by A. Richard Thompson and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-02-22 with Science categories.
This book is open access under a CC BY-NC 4.0 license. The third edition of this indispensable book in radio interferometry provides extensive updates to the second edition, including results and technical advances from the past decade; discussion of arrays that now span the full range of the radio part of the electromagnetic spectrum observable from the ground, 10 MHz to 1 THz; an analysis of factors that affect array speed; and an expanded discussion of digital signal-processing techniques and of scintillation phenomena and the effects of atmospheric water vapor on image distortion, among many other topics. With its comprehensiveness and detailed exposition of all aspects of the theory and practice of radio interferometry and synthesis imaging, this book has established itself as a standard reference in the field. It begins with an overview of the basic principles of radio astronomy, a short history of the development of radio interferometry, and an elementary discussion of the operation of an interferometer. From this foundation, it delves into the underlying relationships of interferometry, sets forth the coordinate systems and parameters to describe synthesis imaging, and examines configurations of antennas for multielement synthesis arrays. Various aspects of the design and response of receiving systems are discussed, as well as the special requirements of very-long-baseline interferometry (VLBI), image reconstruction, and recent developments in image enhancement techniques and astrometric observations. Also discussed are propagation effects in the media between the source and the observer, and radio interference, factors that limit performance. Related techniques are introduced, including intensity interferometry, optical interferometry, lunar occultations, tracking of satellites in Earth orbit, interferometry for remote Earth sensing, and holographic measurements of antenna surfaces. This book will benefit anyone who is interested in radio interferometry techniques for astronomy, astrometry, geodesy, or electrical engineering.
Astrometry Of Fundamental Catalogues
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Author : Hans G. Walter
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Astrometry Of Fundamental Catalogues written by Hans G. Walter and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.
Celestial fundamental catalogues are a prerequisite for the determination of absolute positions and motions in space. Presently, positional astrometry is at the watershed between classical fundamental catalogues, based on moving reference stars, and modern catalogues, based on extragalactic reference objects with non-measurable motion. This book addresses the concepts and methods of the respective construction techniques leading to the stellar frame of the FK5 (fifth fundamental catalogue) and to the newly adopted extragalactic radio reference frame, ICRF (international celestial reference frame), with its extension to optical wavelengths by the Hipparcos Catalogue. While principal outlines of meridian circle observations are given, emphasis is put in some detail on the VLBI technique as applied to astrometry, and to the observational techniques used in the Hipparcos mission, including the tie of the originally non-anchored rigid Hipparcos sphere into the ICRF.
Interferometry And Synthesis In Radio Astronomy
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Author : A. Richard Thompson
language : en
Publisher: John Wiley & Sons
Release Date : 2024-11-12
Interferometry And Synthesis In Radio Astronomy written by A. Richard Thompson and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-11-12 with Science categories.
In this second edition of Interferometry and Synthesis in Radio Astronomy, three leading figures in the development of large imaging arrays, including very-long-baseline interferometry (VLBI), describe and explain the technology that provides images of the universe with an angular resolution as fine as 1/20,000 of an arcsecond. This comprehensive volume begins with a historical review followed by detailed coverage of the theory of interferometry and synthesis imaging, analysis of interferometer response, geometrical relationships, polarimetry, antennas, and arrays. Discussion of the receiving system continues with analysis of the response to signals and noise, analog design requirements, and digital signal processing. The authors detail special requirements of VLBI including atomic frequency standards, broadband recording systems, and antennas in orbit. Further major topics include: Calibration of data and synthesis of images Image enhancement using nonlinear algorithms Techniques for astrometry and geodesy Propagation in the neutral atmosphere and ionized media Radio interference Related techniques: intensity interferometry, moon occultations, antenna holography, and optical interferometry ”This edition meets current demands by providing a comprehensive account of the techniques used today.“ (La Doc STI) [...] The up-to-date edition of Thompson [...] with its exhaustive bibliography, becomes the indispensable source of background for those already in, or considering, radio astronomy.“ (The Observatory)
Modern Astrometry
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Author : Jean Kovalevsky
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-03-09
Modern Astrometry written by Jean Kovalevsky and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-03-09 with Science categories.
Astrometry is the domain of astronomy devoted to the determination of po sitions and their time-variations, and by extension, the apparent dimensions and shapes of celestial bodies. Although several books describe the theoretical foundations of positional astronomy, they touch only slightly on the descrip tion of instruments and the procedures for obtaining actual geometrical or kinematic quantities, which are among the basic observational data in the study of the Universe and of its components. The goal of the present book is, in contrast, to provide an up-to-date description of astrometric techniques, particularly the most recent and powerful ones, whether the instruments are on the ground or in space. Until the end of the 19th century, before the development of physical as tronomy, all astronomical observations were directed towards obtaining posi tions of celestial bodies. Since then astrophysics has become the most impor tant domain of astronomy. With the extension of observations to almost all wavelengths from radio waves to gamma rays, with the use of very sensitive new receivers and the development of fast computers, remarkable progress has been made in the description and the understanding of the Universe.