This symposium was devoted to a new celestial mechanics whose aim has become the study of such objects' as the planetary system, planetary rings, the asteroidal belt, meteor swarms, satellite systems, comet families, the zodiacal cloud, the preplanetary nebula, etc. When the three-body problem is considered instead of individual orbits we are, now, looking for the topology of extended regions of its phase space. This Symposium was one step in the effort to close the ties between two scientific families: the observationally-oriented scientists and the theoretically-oriented scientists.

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...

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...

The concept of Stellar Populations has played a fundamental role in astronomy in the last few decades. It was introduced by Walter Baade after he was able to resolve the Andromeda Nebula and its companions into stars when he used red-sensitive plates and realised that there were two fundamentally different Herzsprung-Russell diagrams in our and these nearby galaxies (common stars in the solar neighborhood versus globular clusters). This result was published in two papers in 1944 in volume 100 of the Astrophysical Journal. Subsequent research gave the concept a much firmer basis and at the...

IAU Symposium No. 167 brought together researchers who use CCDs and arrays, designers and manufacturers of CCDs and Array Mosaics and those who write the software to control these devices and to reduce the large amounts of data contained in each frame.
At the meeting such topics as plans for applying the new technology to the new large telescopes that have been built recently and those planned in the near future, new developments in infrared arrays, advances and concerns with the use of CCDs in photometry and spectroscopy and the creation of large mosaics in photometry and spectroscopy...

IAU symposium 165 'Compact Stars in Binaries' was held from 15 through 19 August 1994, as part of the 22nd General Assembly of the IAU in The Hague. The symposium, supported by IAU Commissions 35,37,44 and 48, and co-sponsored by Commission 42, was attended by about 400 to 500 participants. This symposium received support from: - The International Astronomical Union; - The Royal Netherlands Academy of Sciences; - The Netherlands Ministery of Education and Science; - The Leids Kerkhoven Bosscha Fonds; - The Stichting Fysica. The field of compact stars in binaries is one of the most active...

In the past decade, indirect (Doppler) imaging techniques have opened up a whole new discipline in stellar astronomy, providing increasingly detailed photometric, magnetic, and chemical inhomogeneity images of stellar surfaces. Furthermore, new optical interferometers are already being used with sophisticated interferometer techniques to image stellar surface structures more directly, and in the future the ESO VLT Interferometer and other instruments will extend these capabilities enormously. These developments are highlighted in the first two sections of this book.
The large number of...

This volume reviews recent progress in the study of dynamics of star clusters. The meeting focused on the enormous progress of both the observation and the theoretical modeling of star clusters. New results from the refurbished Hubble Space Telescope (HST) include the mass function down to the hydrogen burning limits, white dwarf sequence, and central density profiles of post-collapse' clusters by star counts. On the theoretical side, this symposium saw the first direct evidence of gravothermal oscillation through N-body simulation, which was made possible by GRAPE-4, the dedicated...

This volume reviews recent progress in the study of dynamics of star clusters. The meeting focused on the enormous progress of both the observation and the theoretical modeling of star clusters. New results from the refurbished Hubble Space Telescope (HST) include the mass function down to the hydrogen burning limits, white dwarf sequence, and central density profiles of post-collapse' clusters by star counts. On the theoretical side, this symposium saw the first direct evidence of gravothermal oscillation through N-body simulation, which was made possible by GRAPE-4, the dedicated...

IAU Symposium 172 Dynamics, Ephemerides and Astrometry of the Solar System was held in Paris in July, 1995. 250 scientists from 33 countries attended the symposium; 24 invited lectures and 165 contributed papers were presented (117 of which were posters). The papers covered topics on celestial mechanics (chaos and evolution of the solar system, asteroids, theories of the motion of the planets, the moon and the natural satellites), methods (symplectic mappings and elliptic functions), astrometry (CCD observations, VLBI and radar observations), ephemerides (representation and...