The book "Relativity in Astrometry, Celestial Mechanics and Geodesy" repre sents a significant contribution to modern relativistic celestial mechanics and astrometry. In these branches of astronomy the theory of general relativity is used nowadays as an efficient practical framework for constructing accurate dynamical theories of motion of celestial bodies and discussing high-precision observations. The author develops the useful tools for this purpose and intro duces the reader into the modern state of the art in these domains. More specifically, the distinctive feature of the book is the wide application of the tetrad formalism to astronomical problems. One may not agree with the author's opinion that this is the only method so far to be able to treat the rel ativistic astronomical problems in a consistent and satisfactory manner. (On the contrary, one may foresee in the nearest future other books on relativistic celestial mechanics and astrometry based on different approaches solving the same problems. ) However, we are now at the beginning of practical relativis tic astronomy and it will demand much effort to reconstruct in a relativistic manner all Newtonian conceptions of ephemeris astronomy and geodesy. In particular, this concern. s the definitions of reference frames, time scales and astronomical units of measurement. This book is one of the first steps in the correct direction. V. A.

This authoritative book presents the theoretical development of gravitational physics as it applies to the dynamics of celestial bodies and the analysis of precise astronomical observations. In so doing, it fills the need for a textbook that teaches modern dynamical astronomy with a strong emphasis on the relativistic aspects of the subject produced by the curved geometry of four-dimensional spacetime. The first three chapters review the fundamental principles of celestial mechanics and of special and general relativity. This background material forms the basis for understanding relativistic reference frames, the celestial mechanics of N-body systems, and high-precision astrometry, navigation, and geodesy, which are then treated in the following five chapters. The final chapter provides an overview of the new field of applied relativity, based on recent recommendations from the International Astronomical Union. The book is suitable for teaching advanced undergraduate honors programs and graduate courses, while equally serving as a reference for professional research scientists working in relativity and dynamical astronomy. The authors bring their extensive theoretical and practical experience to the subject. Sergei Kopeikin is a professor at the University of Missouri, while Michael Efroimsky and George Kaplan work at the United States Naval Observatory, one of the world?s premier institutions for expertise in astrometry, celestial mechanics, and timekeeping.

In the late 20th and beginning 21st century high-precision astronomy, positioning and metrology strongly rely on general relativity. Supported by exercises and solutions this book offers graduate students and researchers entering those fields a self-contained and exhaustive but accessible treatment of applied general relativity. The book is written in a homogenous (graduate level textbook) style allowing the reader to understand the arguments step by step. It first introduces the mathematical and theoretical foundations of gravity theory and then concentrates on its general relativistic applications: clock rates, clock sychronization, establishment of time scales, astronomical references frames, relativistic astrometry, celestial mechanics and metrology. The authors present up-to-date relativistic models for applied techniques such as Satellite LASER Ranging (SLR), Lunar LASER Ranging (LLR), Globale Navigation Satellite Systems (GNSS), Very Large Baseline Interferometry (VLBI), radar measurements, gyroscopes and pulsar timing. A list of acronyms helps the reader keep an overview and a mathematical appendix provides required functions and terms.

IAU S261 summarizes the present state of applied relativity, and discusses the applications and future tests of general relativity.

The high accuracy of modern astronomical spatial-temporal reference systems has made them considerably complex. This book offers a comprehensive overview of such systems. It begins with a discussion of ‘The Problem of Time’, including recent developments in the art of clock making (e.g., optical clocks) and various time scales. The authors address the definitions and realization of spatial coordinates by reference to remote celestial objects such as quasars. After an extensive treatment of classical equinox-based coordinates, new paradigms for setting up a celestial reference system are introduced that no longer refer to the translational and rotational motion of the Earth. The role of relativity in the definition and realization of such systems is clarified. The topics presented in this book are complemented by exercises (with solutions). The authors offer a series of files, written in Maple, a standard computer algebra system, to help readers get a feel for the various models and orders of magnitude. Beyond astrometry, the main fields of application of high-precision astronomical spatial-temporal reference systems and frames are navigation (GPS, interplanetary spacecraft navigation) and global geodynamics, which provide a high-precision Celestial Reference System and its link to any terrestrial spatial-temporal reference system. Mankind’s urgent environmental questions can only be answered in the context of appropriate reference systems in which both aspects, space and time, are realized with a sufficiently high level of accuracy. This book addresses all those interested in high-precision reference systems and the various techniques (GPS, Very Long Baseline Interferometry, Satellite Laser Ranging, Lunar Laser Ranging) necessary for their realization, including the production and dissemination of time signals.

General Relativity Research Trends

Astrometry encompasses all that is necessary to provide the positions and motions of celestial bodies. This includes observational techniques, instrumentation, processing and analysis of observational data, reference systems and frames, and the resulting astronomical phenomena. Astrometry is fundamental to all other fields of astronomy, from the pointing of telescopes, to navigation and guidance systems, to distance and motion determinations for astrophysics. In the last few decades, new observational techniques have enabled improvements in accuracy by orders of magnitude. Starting from basic principles, this book provides the fundamentals for this new astrometry at milli- and micro-arcsecond accuracies. Topics include: basics of general relativity; co-ordinate systems; vectors, tensors, quaternions, and observational uncertainties; determination and use of the celestial and terrestrial reference systems and frames; applications of new observational techniques; present and future star catalogues and double star astrometry. This comprehensive reference will be invaluable for graduate students and research astronomers.