Astronomy, space and time

Infrared astronomy has undergone an enormous revolution during the last decade.

The morphological scheme devised by Hubble and followers to classify galaxies has proven over many decades to be quite effective in directing our quest for the fundamental pa- rameters describing the extragalactic manifold.

Classical stellar evolution theories have undergone some drastic changes in recent decades.

Clusters and superclusters of galaxies are the largest objects in the Universe.

Small and large telescopes are being installed all around the world.

One approach to learning about stellar populations is to study them at three different levels of resolution.

More than two centuries have elapsed since the story of the interacting binary stars began with the rediscovery of the variability of Algol by John Goodricke and the interpretation he proposed for explaining the regular periodic brightness variations which he found.

International Weather Radar Networking covers all aspects of the subject in a collection of contributions drawn from all over the world.

Planetary nebulae are a keystone for the understanding of the evolution of stars, for deep insights into the physical processes prevailing in highly excited dilute nebulae, and for the chemical evolution in galaxies.

The European Workshop on White Dwarfs was initiated by Prof.

Otto von Guericke has been called a neglected genius, overlooked by most modern scholars, scientists, and laymen.

The original plans for a meeting to celebrate the second centenary of the As- tronomical Observatory of Palermo were for a celebration with a double character.

Among the most influential, world-renowned scientists during the early decades of the twentieth century was the Dutch astronomer Jacobus Cornelius Kapteyn (1851-1922).

This volume contains the lectures presented at the second course of the International School of Space Chemistry held in Erice (Sicily) from October 20 - 30 1991 at the "e;E.

Infrared Solar Physics contains the proceedings of the 154th Symposium of the International Astronomical Union held in Tucson, Arizona, March 2--5, 1992.

In the last few years great improvements in the study of stellar jets and bipolar outflows have been achieved, both observationally and theoretically.

Fans of "e;Asterix the Gallic"e; know well that the only fear of people in Brittany is that the sky falls upon their head.

In July 1992, over 300 astronomers attended the Third Tetons Summer School on the subject of `The Environment and Evolution of Galaxies'.

In this review talk, I would like to report on the proper motion analysis, which has been recently carried out together with M.

The numerous applications of optimal control theory have given an incentive to the development of approximate techniques aimed at the construction of control laws and the optimization of dynamical systems.

Cosmic electrodynamics is the specific branch of plasma physics which studies electromagnetic phenomena -- mostly the role of electromagnetic forces in dynamics of highly-conducting compressible medium in the solar interior and atmosphere, solar wind, in the Earth's magnetosphere and magnetospheres of other planets as well as pulsars and other astrophysical objects.

Long-term monitoring is of fundamental significance in solving many important problems in astrophysics and, furthermore, has unequalled value in extending observational runs with small telescopes for the education of young astronomers in order to teach them how to secure high-quality observational data over many years.

`Are there other planetary systems like ours?

THE MEETING The IAU Symposium 160 ASTEROIDS COMETS METEORS 1999 has been held at Villa Carlotta in Belgirate, on the shore of Lago Maggiore (Italy), from June 14 to June 18, 1993.

H.

Prof.

IAU Transactions are published as a volume corresponding to each General Assembly.

Massive stars occupy an exceptional place in general astrophysics.

The idea for another conference on the theme of Infrared Astronomy with Arrays actually goes back to March 1987.

The nonlinear theory of oscillating systems brings new aspects into the study of variable stars.

In recent years there has been a steadily increasing cross-fertilization between cosmology and particle physics, on both the theoretical and experimental levels.

In this Symposium, researchers specializing in pulsation, rotation, magnetic fields and stellar winds are brought together for the first time in order to broaden our understanding of O and B stars.

The NATO Advanced Study Institute "e;Cosmological Aspects of X-Ray Clus- ters of Galaxies"e; took place in Vel en , Westphalia, Germany, from June 6 to June 18, 1993.

Magnetic energy release plays an important role in a wide variety of cosmic objects such as the Sun, stellar coronae, stellar and galactic accretion disks and pulsars.

This History has its origin in a suggestion, made in September 1990 by former IAU General Secretary Derek McNally, who felt "e;that a 75 year history of the Union was needed before the col- lective memory of those who knew the Union before the Second World War vanished.

The IAU Colloquium No.

Outstanding progress in near-infrared detection technology and in real-time image processing has led astronomers to start undertaking all-sky surveys in the 1--2 mum range (project DENIS in Europe and 2MASS in the U.

Magnetism is one of the basic properties of matter.

nd The 2 SORO Workshop on "e;Mass Supply and Flows in the Solar Corona"e; was held in Marciana Mariana on the island of Elba, Italy, in the week September 27 to October 1, 1993, as part of a series of workshops planned by the Solar Corona and Particles Working Group of the SOHO Science Working Team (SWT).

The area of diffuse astrophysical media is enormous and ranges over circum- stellar to extragalactic scales.

In the early summer of '89 a very informal meeting on the bulge of our Galaxy was held in Leiden.

The 1990s are proving to be a very exciting p&iod for high angular resolution astronomy.

Accretion disks in astrophysics represent the characteristic flow by which compact bodies accrete mass from their environment.

ROSAT Observations G.

Our Galactic center's proximity allows astronomers to study physical pro- cesses within galactic nuclei at a level of detail that will never be possible in the more distant, but usually also more spectacular, extragalactic systems.