The twentieth century has been a remarkable epoch in the affairs of men, and this is no less true of astronomy, at once the oldest and most modern of the sciences. Sky watchers at the beginning of the century measured positions and predicted celestial motions in faithful but uninspired homage to the Muse Urania; nowadays, their descendents call on all the resources of modern science to probe the nature and evolution of a bewildering range of celestial objects. Man has even set out to call personally on his nearest neighbours in space. Professor Zdenek Kopal has lived and practised astronomy...

Eclipsing Variables - What They can Tell Us and What We can do with Them The aim of the present book will be to provide an introduction to the inter- pretation of the observed light changes of eclipsing binary stars and their analysis for the elements of the respective systems. Whenever we study the properties of any celestial body - be it a planet or a star - all information we wish to gain can reach us through two different channels: their gravitational attraction, and their light. Gravitational interaction between our Earth and its celestial neighbours is, however, measurable only at...

Eclipsing Variables - What They can Tell Us and What We can do with Them The aim of the present book will be to provide an introduction to the inter- pretation of the observed light changes of eclipsing binary stars and their analysis for the elements of the respective systems. Whenever we study the properties of any celestial body - be it a planet or a star - all information we wish to gain can reach us through two different channels: their gravitational attraction, and their light. Gravitational interaction between our Earth and its celestial neighbours is, however, measurable only at...

Our conference - opening today - has two aims in view: first, to commemorate some milestones in the development of the studies of close binary systems whose anniversaries fall in these years, as well as to take stock of our present knowledge accumulated through out preceding decades, in order to consider where do we go from here. This summer, 310 years will have elapsed since the first ec lipsing binary - Algol - was discovered in Bologna by Geminiano Montanari (1633-1687) to be a variable star; and 198 years have gone by since John Goodricke of York (1764-1786) established the fact that...

The words of this preface were written when the book was ready to go to the press; and are limited to only a few points which are best made in this place. As is intimated by the sub-title, the whole volume was written with appli cations in mind to double-star astronomy. The latter is, however, not the only branch of our science which could benefit from its contents. The same is true of certain aspects of the dynamics of stellar systems or galaxies (the stellar popula tions of which are also characterized by the fact that the mean-free-path of their constituent stars are long in comparison...

The aim of the present book will be to summarize the results of the space exploration of the Moon in the past fifteen years -culminating in the manned Apollo missions of 1969-1972 -on the background of our previous acquaintance with our satellite made in the past by astronomical observations at a distance. Astronomy is one of the oldest branches of science conceived by the inquisitive human mind; though until quite recently it had been debarred from the status of a genuine experimental science by the remoteness of the objects of its study. With the sole exception of meteoritic matter which...

The Bosscha Observatory in Lembang, Java, Indonesia, celebrated in 1983 its 60th anniversary. Since its foundation, the physical properties of binary systems have formed a major research topic of this observatory. Until 1970, the study of visual binaries and the determination of orbits received most emphasis. Since then, also the evolution of close binary systems, such as X-ray binaries, Wolf-Rayet binaries and binary pulsars, has been researched with priority in Lembang. It seemed thus appropriate that a Colloquium devoted to the study of binary systems be held in Lembang at the time of the...

If Zdenek Kopal Department of Astronomy University of Manchester Your Magnificences, my Lord Mayor, ladies and gentlemen! It is a great pleasure for me to respond, on behalf of your foreign guests, to your gracious words of welcome; and to thank you for the wonderful reception which you nave extended to us. The city of Bamberg and its Remeis Sternwarte nas indeed been renowned allover the world for a great many years - as the place where your Observatory's first director, Professor Ernst Hartwig (1851-1923) - in addition to his other titles to fame - collaborated (with Gustav Muller of...

A favourable reception of the first edition of this book - due no doubt to the nature of its subject - which went out of print in 2 years, gave its author a welcome oppor tunity to update at present its contents. This was all the more necessary, as seldom in the annals of science has our knowledge of the physics and astronomy of the Moon made greater progress than during this time. The real heroes of this advance have, of course, been the spacecraft - 33 of which have now been sent out since 1959 to reconnoiter our satellite at a close range. The hard-landers among them just about delivered...

After many decades spent in astronomical semi-obscurity, the Moon has of late suddenly emerged to claim renewed interest on the part of the students of astronomy, as well as of other branches of physical science and technology; and the reasons which brought this about are indeed of historical significance. From time immemorial, astronomy has been debarred from the status of a gen- uine experimental science by the utter remoteness of the objects of its study. With the exception of meteors - those small freaks of cosmic matter intercepted by the Earth on its perpetual journey through space -...