Astrometry encompasses all that is necessary to measure the positions and motions of celestial bodies: observational techniques, instrumentation, processing and analysis of observational data, and reference systems and frames, as well as the resulting astronomical phenomena. It is fundamental to all other fields of astronomy, from the focusing of telescopes to navigation and guidance systems and distance and motion determinations for astrophysics. Starting from basic principles, this work provides the principles of astrometry at milli- and micro-arcsecond accuracies and will be an invaluable...

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...

This volume contains papers presented at the US/European Celestial Mecha- nics Workshop organized by the Astronomical Observatory of Adam Mickiewicz University in Poznan, Poland and held in Poznan, from 3 to 7 July 2000. The purpose of the workshop was to identify future research in celestial mech- anics and encourage collaboration among scientists from eastem and westem coun- tries. There was a full program of invited and contributed presentations on selected subjects and each day ended with a discussion period on a general subject in celestial mechanics. The discussion topics and the...

General relativity provides our best description of gravitation in modern physics currently all observations and tests of gravitational theories have agreed with it. GR is applied in fields as diverse as fundamental astronomy, astrophysics, geodesy, physics, and space sciences, where high-accuracy observations and measurements are taken or modeled. IAU Symposium 261 summarizes the present state of applied relativity. It considers the applications of general relativity in a wide range of disciplines: geodesy, navigation, solar system ephemerides, space missions, pulsar timing, high-accuracy...

This text records the recent events in the development of astrometry. The results of space missions in astrometry, Hipparcos and some results from the Hubble Space telescope are presented. Combined with ground-based results, this provides astrometry results at milliarcsecond resolution. At the same time, the extragalactic reference frame, based on very long baseline interferometry radio positions, is being introduced as the fundamental reference frame. It is now also evident that future optical interferometry space missions can provide an additional improvement in future of orders of...

This volume contains papers presented at the US/European Celestial Mecha nics Workshop organized by the Astronomical Observatory of Adam Mickiewicz University in Poznan, Poland and held in Poznan, from 3 to 7 July 2000. The purpose of the workshop was to identify future research in celestial mech anics and encourage collaboration among scientists from eastem and westem coun tries. There was a full program of invited and contributed presentations on selected subjects and each day ended with a discussion period on a general subject in celestial mechanics. The discussion topics and the leaders...

"Fundamental Astronomy and Solar System Dynamics", a program of invited papers honoring Professor Walter Fricke, who for thirty years has been Director of the Astronomisches Rechen lnstitut in Heidelberg, was held at the Thompson Conference Center of the University of Texas at Austin on Wednesday 27 March 1985 on the occasion of his seventieth birthday and retirement as Director of ARl. Professor Fricke's contributions to astronomy encompass the areas of galactic dynamics, radial velocities, stellar statistics. the fundamental reference system and the constant of precession. Participants were...

This volume is designed as an introductory text and reference book for graduate students, researchers and practitioners in the fields of astronomy, astrodynamics, satellite systems, space sciences and astrophysics.