Zdenek Kopal – författare

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 with the dimensions of the respective systems); the central condensations of which are high enough to approximate the gravitational action of a "mass-point". This fact did not, to be sure, escape the attention of previous investigators (in the case of globular clusters, in particular, the Roche model was introduced in their studies under the guise of polytropic models characterized by the index n = 5); though no particular attention will be paid to these in this book. But possible applications of the Roche model are not limited to problems arising in stellar astrophysics. With Coulomb forces replacing gravitation, the equilibrium model finds a close analogy in the field of electrostatics-as was pointed out already at the beginning of this century by (then young) J. H. Jeans (cf.

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 throughout this efflorescence of his subject. Born in Czechoslovakia just before the outbreak of the Great War, and educated in the classical European tradition, he knows well the days when scholars commanded such respect that astronomical congresses would be visited by Heads of State. Yet within his own lifetime, he has himself been recruited to play an important role in scientific preparations for a manned Moon landing. He has known and worked with some of the most highly respected practitioners of Modern Astromomy: Russell, Shapley, Urey in the United States, Eddington in Britain. His fine eye for detail, coupled with his strong sense of history, enable him to unfold through his personal recollections the development of his subject across the social changes of two world wars. Inspired by his grandfather, who would think nothing of walking sixty miles to theatrical performance, the young Kopal acquired a Wanderlust that has taken him in his career more than a dozen times rond the world. He has visited the most ancient observatories, observed solar eclipses in Japan and Java, helped to establish new institutions in Iraq and India, and commuted for many years between the Old and New Worlds. He has toiled in every corner of his chosen vinyard: as observer, outstanding theoretician, populariser, editor and teacher. During his thirty years as Professor of Astronomy at Manchester, he helped to educate over a hundered PhD students, many from the developing world, who have taken the torch of astronomy back to their home lands. In retirement, he continues to direct his efforts towards a better understanding of the Universe, and shows no sign of abandoning his life-long affair with the heavens. Professor Kopal has entitled his book Of Stars and Men, for he has delighted in the company of both throughout his life. The reader is invited to share with him the story of his birth, his education, his work and his travels; and to join with him in contemplating the history and possible future of his subject, and of civilisation itself.

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 throughout this efflorescence of his subject. Born in Czechoslovakia just before the outbreak of the Great War, and educated in the classical European tradition, he knows well the days when scholars commanded such respect that astronomical congresses would be visited by Heads of State. Yet within his own lifetime, he has himself been recruited to play an important role in scientific preparations for a manned Moon landing. He has known and worked with some of the most highly respected practitioners of Modern Astromomy: Russell, Shapley, Urey in the United States, Eddington in Britain. His fine eye for detail, coupled with his strong sense of history, enable him to unfold through his personal recollections the development of his subject across the social changes of two world wars. Inspired by his grandfather, who would think nothing of walking sixty miles to theatrical performance, the young Kopal acquired a Wanderlust that has taken him in his career more than a dozen times rond the world. He has visited the most ancient observatories, observed solar eclipses in Japan and Java, helped to establish new institutions in Iraq and India, and commuted for many years between the Old and New Worlds. He has toiled in every corner of his chosen vinyard: as observer, outstanding theoretician, populariser, editor and teacher. During his thirty years as Professor of Astronomy at Manchester, he

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 throughout this efflorescence of his subject. Born in Czechoslovakia just before the outbreak of the Great War, and educated in the classical European tradition, he knows well the days when scholars commanded such respect that astronomical congresses would be visited by Heads of State. Yet within his own lifetime, he has himself been recruited to play an important role in scientific preparations for a manned Moon landing. He has known and worked with some of the most highly respected practitioners of Modern Astromomy: Russell, Shapley, Urey in the United States, Eddington in Britain. His fine eye for detail, coupled with his strong sense of history, enable him to unfold through his personal recollections the development of his subject across the social changes of two world wars. Inspired by his grandfather, who would think nothing of walking sixty miles to theatrical performance, the young Kopal acquired a Wanderlust that has taken him in his career more than a dozen times rond the world. He has visited the most ancient observatories, observed solar eclipses in Japan and Java, helped to establish new institutions in Iraq and India, and commuted for many years between the Old and New Worlds. He has toiled in every corner of his chosen vinyard: as observer, outstanding theoretician, populariser, editor and teacher. During his thirty years as Professor of Astronomy at Manchester, he

Advances in Astronomy and Astrophysics, Volume 7 covers reviews about the advances in astronomy and astrophysics. The book presents reviews on the scattering of electrons by diatomic molecules and on Babcock''s theory of the 22-year solar cycle and the latitude drift of the sunspot zone. The text then describes reviews on the structures of the terrestrial planets (Earth, Venus, Mars, Mercury) and on type III solar radio bursts. The compact and dispersed cosmic matter is also considered with regard to the search for new cosmic objects and phenomena and on the nature of the ref shift from compact galaxies. Astronomers and astrophysicists will find the book invaluable.

Advances in Astronomy and Astrophysics, Volume 8 presents reviews on the advances in astronomy and astrophysics. The book discusses microwave studies of thermal emission from the moon; the origin of the thermal emission of the moon at microwave frequencies; and the effect of various specific surface attributes on the characteristics of the microwave emission. The text then describes radar studies of the moon, including radar studies of the moon''s motions and of the statistical properties of the lunar surface and radar mapping of the lunar surface. The theoretical basis of cratering and erosion of the moon''s surface is also considered. Astronomers, astrophysicists, and students taking astronomy and astrophysics will find the book useful.

Advances in Astronomy and Astrophysics, Volume 9 covers reviews on the advances in astronomy and astrophysics. The book presents reviews on the Roche model and its applications to close binary systems. The text then describes the part played by lunar eclipses in the evolution of astronomy; the classical theory of lunar eclipses; deviations from geometrical theory; and the methods of photometric observations of eclipses. The problems of other phenomena related in one way or another to lunar eclipses are also considered. The book further tackles the infrared observation on the eclipsed moon, as well as some of the experimental measurements at infrared wavelengths which have proved useful in evaluating various theoretical models and, more generally, in specifying the radiation environment on the lunar surface. Astronomers, astrophysicists, and students taking related courses will find the book invaluable.

Advances in Astronomy and Astrophysics, Volume 1 brings together numerous research works on different aspects of astronomy and astrophysics. This book is divided into five chapters and begins with an observational summary of the shock-wave theory of novae. The subsequent chapter provides the properties and problems of T tauri stars and related objects. These topics are followed by discussions on the structure and origin of meteorites and cosmic dust, as well as the models for evaluation of mass distribution in oblate stellar systems. The final chapter describes the methods of polarization measurements of starlight. This book is of value to astronomers, astrophysicists, and researchers in the allied fields.

Advances in Astronomy and Astrophysics, Volume 2 brings together numerous research works on different aspects of astronomy and astrophysics. This volume is composed of six chapters and begins with a summary of observational record on twilight extensions of the Venus cusps. The next chapter deals with the common and related properties of binary stars, with emphasis on the evaluation of their cataclysmic variables. Cataclysmic variables refer to an object in one of three classes: dwarf nova, nova, or supernova. These topics are followed by discussions on the eclipse phenomena and the eclipses in the domain of the radio waves and of the artificial satellites. A chapter discusses the discovery, colors, spectra, motions, luminosities, and frequency in space of white dwarf stars. The concluding chapters examine the occurrence and capture of stray bodies in the solar system and the existence of Magellanic clouds. This book will prove useful to astronomers and astrophysicists.

Advances in Astronomy and Astrophysics, Volume 3 is a collection of papers that describes the elements found in the solar atmosphere, Fourier transforms, internal structure of the stars, and apsidal motions. Two papers discuss the spectral analysis of solar flares and a survey of modern cosmology. One paper discusses the solar abundance of particular elements such as iron, sodium, potassium, zinc, gallium, strontium. The loss of heavier elements from the upper layers of the solar atmosphere depends on the atomic number: the heavier the atom the greater the amount of depletion. Another paper describes a method to determine the elements of an eclipsing binary system by defining the characteristic functions of the eclipse derived from some integral transforms of the ascending and descending parts in minima of the light curve. One paper compares the general physical theory of self-gravitating gas spheres and of thermonuclear processes with certain phenomena present in close binary systems. One paper notes that the estimates of electron density made by various methods at different flares (solar) and the resulting optical thickness of flares yield values within a wide range. The differences observed in optical thickness are due to various presuppositions on the broadening mechanism of the Balmer lines. The collection is suitable for astronomers, geochemists, astro-physicists, and scientists whose works involve cosmology.

Advances in Astronomy and Astrophysics, Volume 4 brings together numerous research works on different aspects of astronomy and astrophysics. This volume is composed of five chapters, and starts with a description of objective prism and its application in space observations. The next chapter deals with the possibilities of deriving reliable models of the figure, density distribution, and gravity field of the Moon based on data obtained through Earth-bound telescopes. These topics are followed by a discussion on the ideal partially relativistic, partially degenerate gas in an exact manner. A chapter examines first the effect of exchange of matter on the periods of close binary systems, and then briefly surveys the mechanisms of mass loss, other causes of period changes, and related evolutionary problems. The last chapter looks into the cometary origin of meteorites. This book will prove useful to astronomers and astrophysicists.

Advances in Astronomy and Astrophysics, Volume 5 is a collection of papers that deals with the Zodiacal light, three dimensional periodic oscillations, the secular variation of mass, and the evolution of binary systems. Some papers discuss the periodicity of the sunspot groups, as well as compact and dispersed cosmic matter. One paper notes that the brightness of the zodiacal light continues to increase right up to the limb of the Sun, where it merges with parts of the solar corona. Another paper discusses analytically and numerically the three families of three-dimensional motions where the members of each family pass very close to one of three equilibrium points. One paper describes the loss of mass in the Sun as being (1) caused by electromagnetic or corpuscular radiation that occurs at a slow rate, or (2) by an explosion of a nova or supernova. One paper examines the periodicity of solar activities, the physical conditions of sunspots, chromospheric flares, prominence, and magnetic fields. The paper notes that different periodicity laws govern the formation frequency and importance of spot groups. The behavior of spot groups also depends on the periodicity process of solar activity. The collection can prove valuable for astro-physicists, astronomers, geochemists, and mathematicians whose works involve cosmology and astronomy.

Advances in Astronomy and Astrophysics, Volume 6 brings together numerous research works on different aspects of astronomy and astrophysics. This volume is composed of five chapters, and starts with the description of improved methods for analyzing and classifying families of periodic orbits in a conservative dynamical system with two degrees of freedom. The next chapter describes the variation of fractional luminosity of distorted components of close binary systems in the course of their revolution, or the accompanying changes in radial velocity. This topic is followed by discussions on various mechanisms that have been proposed for the interstellar medium, as well as the mass exchange and evolution of close binary stars. The concluding chapter examines evidence for lunar luminescence. This book will prove useful to astronomers and astrophysicists.

Physics and Astronomy of the Moon focuses on the application of principles of physics in the study of the moon, including perturbations, equations, light scattering, and photometry. The selection first offers information on the motion of the moon in space and libration of the moon. Topics include Hill''s equations of motion, non-solar perturbations, improved lunar ephemeris, optical and physical libration of the moon, and adjustment of heliometric observations of the moon''s libration. The text then elaborates on the dynamics of the earth-moon system, photometry of the moon, and polarization of moonlight. The publication explains lunar eclipses and the topography of the moon. Discussions focus on the photometric model of eclipses, brightness of the solar elementary ring, effects of light scattering, photometry of lunar eclipses, and determination of altitudes on the moon. The text then evaluates the interpretation of lunar craters, luminescence of the lunar surface, and the origin and history of the moon. The selection is a dependable reference for physicists and astronomers interested in the application of principles of physics in the study of the moon.

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 occasionally finds its way into our labora­ tories, all celestial bodies could be investigated only at a distance: namely, from the effects of attraction exerted by their mass, or from the ciphered messages of their light carried by nimble-footed photons across the intervening gaps of space. A dramatic emergence oflong-range spacecraft -capable of carrying men with their instruments not only outside the confines of our atmosphere, but to the actual surface of our nearest celestial neighbour - has since 1957 thoroughly changed this time­ honoured picture. In particular (as we shall detail in Chapter 1 of this book) space astronomy ofthe Moon is barely 15 years old. But relative infant as it is by age, it has already provided us with such a tremendous amount of new and previously inacces­ sible scientific data as to virtually revolutionalize our subject.

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 distances of the order of the dimensions of our solar system; and the only means of communication with the realm of the stars are their nimble-footed photons reaching us - with appropriate time-lag - across the intervening gaps of space. As long as a star is single and emits constant light, it does not constitute a very revealing source of information. A spectrometry of its light can disclose, to be sure, the temperature (colour, or ionization) of the star's semi-transparent outer layers, their chemical composition, and prevalent pressure (through Stark effect) or magnetic field (Zeeman effect), it can disclose even some information about its absolute luminosity or rate of spin. It cannot, however, tell us anything about what we should like to know most - namely, the mass or size (i.e., density) of the respective configuration; its absolute dimensions, or its internal structure.

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 distances of the order of the dimensions of our solar system; and the only means of communication with the realm of the stars are their nimble-footed photons reaching us - with appropriate time-lag - across the intervening gaps of space. As long as a star is single and emits constant light, it does not constitute a very revealing source of information. A spectrometry of its light can disclose, to be sure, the temperature (colour, or ionization) of the star's semi-transparent outer layers, their chemical composition, and prevalent pressure (through Stark effect) or magnetic field (Zeeman effect), it can disclose even some information about its absolute luminosity or rate of spin. It cannot, however, tell us anything about what we should like to know most - namely, the mass or size (i.e., density) of the respective configuration; its absolute dimensions, or its internal structure.

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 Algol's light changes were periodic. Moreover, it is al­ most exactly (to a month) now 100 years since Edward Charles Pickering (1846-1919) of Harvard Observatory in the United States took the first steps towards the development of systematic methods of analysis of the light changes of Algol and related systems - a topic which will constitute the major part of the programme of our present conference. The three dates recalled above illustrate that the discoverers of such celestial objects and observers of their light changes have been systematically ahead of the theoreticians endea­ vouring to understand the significance of the observed data by de­ cades and centuries in the past - a fact which, incidentally, con­ tinues to hold good (albeit with a diminishing lead-time) up to the present.

Proceedings of the 97th Colloquium of the International Astronomical Union, held in Brussels, Belgium, June 8-13, 1987

ASTRONOMICAL ECLIPSE PHENOMENA In looking over the long history of human science from time immemorial to our own times, it is impossible to overestimate the role played in it by the phenomena of eclipses of the celestial bodies-both within our solar system as well as in the stellar universe at large. Not later than in the 4th century B. C. , the observed features of the shadow cast on the Moon by the Earth during eclipses led Aristotle (384-322 B. C. ) to formulate the first scientific proof worthy of that name of the spherical shape of the Earth; and only somewhat later, the eclipses of the Sun provided Aristarchos (in the early part of the 3rd century B. C. ) or Hipparchos (2nd half ofthe same century) with the geometric means to ascertain the distance which separates the Earth from the Sun. In the 17th century A. D. (in 1676, to be exact) the timings of the eclipses of the satellites of Jupiter by their central planet enabled Olaf Romer to discover that the velocity with which light propagates through space is finite.

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 with the dimensions of the respective systems); the central condensations of which are high enough to approximate the gravitational action of a "mass-point". This fact did not, to be sure, escape the attention of previous investigators (in the case of globular clusters, in particular, the Roche model was introduced in their studies under the guise of polytropic models characterized by the index n = 5); though no particular attention will be paid to these in this book. But possible applications of the Roche model are not limited to problems arising in stellar astrophysics. With Coulomb forces replacing gravitation, the equilibrium model finds a close analogy in the field of electrostatics-as was pointed out already at the beginning of this century by (then young) J. H. Jeans (cf.

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 Observatory''s anniversary. In the Colloquium, the role of wide double (and multiple) systems received special emphasis - not only because of the long tradition of visual binary research at Lembang; but also because their role in documenting stellar evolution has been largely overlooked in recent decades, and needs to be brought into focus with the information forthcoming from close binaries. The Colloquium covered the physical properties of visual as well as close binary systems, and their generic relations, in the broadest possible sense. It was sponsored by the International Astronomical Union as IAU Colloquium No. 80 (''Double Stars, Physical Properties and Generic Relations''). After the official opening ceremony, the meeting started with a discussion on the future of astronomy in Asia. The scientific sessions began with the ''V. Bappu Memorial Lecture on the Evolution of Binary Systems'', presented by Z. Kopal.

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 Observatory's anniversary. In the Colloquium, the role of wide double (and multiple) systems received special emphasis - not only because of the long tradition of visual binary research at Lembang; but also because their role in documenting stellar evolution has been largely overlooked in recent decades, and needs to be brought into focus with the information forthcoming from close binaries. The Colloquium covered the physical properties of visual as well as close binary systems, and their generic relations, in the broadest possible sense. It was sponsored by the International Astronomical Union as IAU Colloquium No. 80 ('Double Stars, Physical Properties and Generic Relations'). After the official opening ceremony, the meeting started with a discussion on the future of astronomy in Asia. The scientific sessions began with the 'V. Bappu Memorial Lecture on the Evolution of Binary Systems', presented by Z. Kopal.

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 Potsdam) on the construc- tion of the monumental Geschichte und Literatur des Lirhtwechsels der Veranderlichen Sterne, which since 1918 has (together with its sub- sequent continuation) been a veritable vade-mecum of a1l students of variable stars; where the second director, Professor Ernst Zinner (1886-19]~ prepared his valuable Katalog der Verdachtigen Veranderlichen Sterne (192@ which safeguarded many an astronomer (including the present speaker in the days of his innocence) from premature discovery claims; and whose third director, Professor Wolfgang Strohmeier, initiated in 1959 the tradition of the international colloquia of which ours is the latest successor. It is indeed a great pleasure to welcome Professor Strohmeier - now Emeritus - among us; and to congratulate him on the grace with which he is carrying his years.