This volume contains the fifteenth tri-annual reports of the Presidents of the forty Commissions of the International Astronomical Union; it refers to the progress in our discipline during the three years 1970, 1971 and 1972. As compared to earlier volumes a gradual change in character is unmistakable. The ever increasing flow of publications, combined with the obvious necessity to keep the Reports at a reasonable size and price level has gradually forced the Commission Presidents to be more selective than before in drafting their Reports. I have certainly stimulated them into that direction - in order that Reports like these be valuable and lasting, it seems imperative that the individual contributions have the character of a critical overall review, where a fairly complete summary is given of the major develop ments and discoveries of the past three years, and in which the broad developments and new trends be clearly outlined, while at the same time essential problems for future research are identified. With respect to the latter item I have suggested the Commission Presidents to add to their reports a brief section on scientific priorities for future research in the field of their Commissions. In order to save space I have suggested to Commission Presidents that references to published papers are given on the basis of their number in the published issues of Astronomy and Astrophysics Abstracts. For instance, the indication (06. 078. 019) or (AAA 06. 078."

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 recent results, ground-based and space-based, and the lack of a generally accepted dynamo theory with predictive power for the stars and the Sun, result in an ever-growing complexity of interpretation of individual results. The IAU Symposium 176 on Stellar Surface Structure' consequently focused on spatially resolved stellar observations throughout the H-R diagram, from O- and B-stars to late M-stars. Two further sections in this book summarize the current observational data on surface inhomogeneities in stellar photospheres, chromospheres, and coronae. Finally, a special section is devoted to next generation model atmospheres.

The study of the fine structure of solar radio emissions is key to understanding plasma processes in the solar corona. It remains a reliable means for both diagnosing the corona and verifying the results of laboratory plasma experiments on wave-wave and wave-particle interactions. This monograph provides a comprehensive review of the fine structure of solar radio bursts. Based on the diversity of experimental data resulting from the progress made in observational techniques, the validity of various theoretical models is reexamined. The book serves as an up-to-date reference work for all researchers in this field.

In the first book which deals entirely with the subject of time in Africa and the Black Diaspora, Adjaye presents ten critical case studies of selected communities in Africa, the Caribbean, and the American South. The essays cover a wide spectrum of manifestations of temporal experience, including cosmological and genealogical time, physical and ecological cycles, time and worldview, social rhythm, agricultural and industrial time, and historical processes and consciousness. The studies confirm the continuity of temporal experience among Africans from pre-colonial times, through the colonial period in Africa, across continents through slavery and Maroon societies, to present-day communities like the Gullah of the Sea Islands of South Carolina. The subject of time, now recognized to be relative rather than uniform, draws together evidence from a variety of disciplines, specifically history, linguistics, political science, anthropology, and philosophy.

This book with its clear explanation of the nature of the universe assumes no prior knowledge of astronomy or cosmology and so will attract interested public and new amateur astronomers.It provides much more on large-scale structures than other popular-level cosmology books. The mix of cosmology /large scale structures/anthropic principle and perspective on the universe should, as far as the author knows, be unique. A special colour feature incorporated in the book will offer three-dimensional views of the surrounding universe to ever greater depths.

ROSAT Observations G. HASINGER Max-Planck-Institut flir extraterrestrische Physik, D-85740 Garching, Germany Abstract. This review describes the most recent advances in the study of the extragalactic soft X-ray background and what we can learn about its constituents. The deepest pointed observations with the ROSAT PSPC are discussed. The logN-logS relation is presented, which reaches to the faintest X-ray fluxes and to the highest AGN surface densities ever achieved. The N(>S) relation shows a 2 density in excess of 400 deg- at the faintest fluxes and a flattening below the Einstein Deep Survey limit. About 60% of the extragalactic background has been resolved in the deepest field. Detailed source spectra and first optical and radio identifications will be discussed. The results are put into perspective of the higher energy X -ray background. Key words: X-rays, background radiations, active galactic nuclei. 1. Introduction The extragalactic X-ray background (XRB), discovered about 30 years ago, has been studied extensively with many X-ray experiments, in particular with the satel lites HEAO I and II (see ego Boldt 1987) and with ROSAT (e. g. Hasinger et aI. , 1993). Figure 1 shows a compilation of some of the most recent spectral measure ments for the X-ray background. Over the energy range from 3 to about 100 keY its spectrum can be well approximated by an optically thin thermal bremsstrahlung model with kT ~ 40 keY, while at lower X-ray energies a steepening into a new component has been observed observed (e. g.

This monograph is the fIrst book exclusively devoted to Dusty and Dirty from a unifIed Electrohydrodynamical point of view, incorporating new Plasmas concepts of Electric Cusp-Reconnection and Generalized Critical Ionization Velocities, based on a survey stimulated from a series of International Wo- shops/Symposia on Plasmas in Space and in the Laboratory held in Tokyo since 1980, and from associations with a number of Universities and Institutions which offered me opportunities to do specifIc research. For example, the subjects of Mirrors and Cusps, Critical Velocities, Double Layers or Dipoles, and Quadrupoles in this monograph were initiated by the fIrst International Workshop on Relation between Laboratory and Space Plasmas held in Tokyo in 1980 which was well received, in this connection in particular thankfully by the late Professor Hannes Alfven with encouraging communica tions, inspiring me to studies of critical velocities, electrical version offield line merging-reconnection, and Unconventional Plasmas. Although the subject of this monograph was partly included also in topics at the URSI Workshop on Nonlinear and Environmental Electromagnetics in 1984, at the second Wo- shop on Relation between Laboratory and Space Plasmas in 1986, and at the URSI Symposium on Environmental and Space Electromagnetics in 1989, the main subject: Dusty and Dirty Plasmas and EHD (electrohydrodynamics) was discussed exclusively at the later Symposium in 1992, resulting in the fIrst monograph, Dusty and Dirty Plasmas with Noise and Chaos in Space and in the Laboratory in this fIeld for which Professor John E.

This book includes nine chapters written by internationally recognized experts, covering all aspects of millisecond pulsars in one concise and cohesive volume. These aspects include pulsations powered by stellar spin, accretion and thermonuclear burning of accreted matter, their physics and utility, stellar evolution and the extreme physics of super-dense stellar cores. The book includes substantial background material as well as recent theoretical and multi-wavelength observational results. The volume will thus be useful for professional astronomers and graduate students alike. What is the behavior of the strong nuclear interaction, and what are the matter constituents at ultrahigh densities in neutron star cores? How do old neutron stars in binaries evolve? How does their magnetosphere interact with the surrounding plasma to accelerate particles and emit radiation observed at all wavelengths? These are just a few of the questions that millisecond pulsars are helping us answer and will settle in the near future with the next generation of instruments. Such quickly rotating, highly magnetized neutron stars are remarkable natural laboratories that allow us to investigate the fundamental constituents of matter and their interactions under extreme conditions that cannot be reproduced in terrestrial laboratories.

This book describes the basic concepts of spacecraft operations for both manned and unmanned missions. The first part of the book provides a brief overview of the space segment. The next four parts deal with the classic areas of space flight operations: mission operations, communications and infrastructure, the flight dynamics system, and the mission planning system. This is followed by a part describing the operational tasks of the various subsystems of a classical satellite in Earth orbit. The last part describes the special requirements of other mission types due to the presence of astronauts, the approach of a satellite to another target satellite, or leaving Earth orbit in interplanetary missions and landing on other planets and moons. The 2nd edition is published seven years after the first edition. It contains four new chapters on flight procedures, the human factors, ground station operation, and software and systems. In addition, several chapters have been extensively expanded. The entire book has been brought up to date and the language has been revised. This book is based on the "Spacecraft Operations Course" held at the German Space Operations Center. However, the target audience of this book is not only the participants of the course, but also students of technical and scientific courses, as well as technically interested people who want to gain a deeper understanding of spacecraft operations.

The Moon has been an object of fascination for religions, cultures, and societies the world over since the dawn of humanity.

The Moon is a beautifully illustrated account of our lunar neighbour in all its guises: a guiding light in the night sky, the driver of oceanic tides and natural cycles, the subject of exhaustive scientific study, and an enduring influence in literature, art, and popular culture.

Exploring theories for the Moon’s origins around 4.5 billion years ago, the book charts its influence on the calendar systems and mythologies of early societies, and its role in the invention of the telescope and the science-fiction genre. It tells the incredible story of the Cold War space race and the first Moon landings. Specially commissioned illustrations capture the Moon's phases and motions in vivid detail, while stunning photography and artefacts bring the rich history of lunar observation and exploration to life.

The last chapter of the book features extensive coverage of NASA’s Artemis mission to return astronauts to the lunar landscape in 2026, paving the way for future missions to Mars. The book also includes a guide to observing the Moon, complete with annotated maps and profiles of key physical features such as Tycho Crater and the Sea of Tranquility.

Straddling science, culture, and history across the world, The Moon is a captivating and richly informative celebration.

Line intensity mapping (LIM) is an observational technique that probes the large-scale structure of the Universe by collecting light from a wide field of the sky. This book demonstrates a novel analysis method for LIM using machine learning (ML) technologies. The author develops a conditional generative adversarial network that separates designated emission signals from sources at different epochs. It thus provides, for the first time, an efficient way to extract signals from LIM data with foreground noise. The method is complementary to conventional statistical methods such as cross-correlation analysis. When applied to three-dimensional LIM data with wavelength information, high reproducibility is achieved under realistic conditions. The book further investigates how the trained machine extracts the signals, and discusses the limitation of the ML methods. Lastly an application of the LIM data to a study of cosmic reionization is presented. This book benefits students and researchers who are interested in using machine learning to multi-dimensional data not only in astronomy but also in general applications.

Seen from "inside the IAU," this book tells the in-depth story of a major crisis in which China "divorced" from the International Astronomical Union in 1960 as a protest against the admission of Taiwan. This happened to all the scientific unions at the same time, and to the Olympic Games, which, unexpectedly, would serve as a laboratory for the "reconciliation" which took place following the re-opening of China to the world 20 years later. The so-called "China conflict" is the most important crisis in the post-WWII history of the IAU. Yet, many details about this conflict and its links to broader geopolitical events have long remained unsettled, obscure, or altogether absent. In particular, the book describes for the first time the "separation" period, which covered the Cultural Revolution, and in which the IAU made desperate official efforts to reach out to China, while some groups of Western and Chinese astronomers managed to keep contact at times. On the occasion of the IAU Centenary celebrations in 2019, the book revisits this painful succession of events using unpublished documents from the IAU Archives and the International Council of Scientific Unions. The book also contains supplementary typescripts of selected handwritten correspondences and the full translation of key original Chinese documents unknown to readers outside China. What emerges is a complex and fascinating story of human relations and science diplomacy under the shadow of the Cold War. Readers will learn how the 20-year "China conflict" as lived by astronomers and scientists is important not only for the history of the IAU, but also for the history of contemporary China. "This book is full of so many original documents of the IAU office, very reliable and good to open to the public readers." Shuhua Ye, Shanghai Observatory (IAU Vice-President, 1988-1994) This book is a companion book to "Astronomers as Diplomats," published at the same time in the same series.

Offering a series of well-defined problems supplemented by solutions, Exercises in Practical Astronomy: Using Photographs presents meaningful practical work in elementary astronomy and astrophysics. The book provides authentic astronomical photographs of very high quality on which different types of objects can be studied with equipment as simple as rulers and protractors. In addition to photographs and a set of exercises that cover 12 topics, the coverage includes ample hints and worked solutions that are designed to enable students to work independently. SI units are used for physical data and in conversions of astronomical quantities. This book is one of the few to use real rather than idealized or simplified data in the problems.

A monograph on inflationary cosmology and cosmological phase transitions, investigating modern cosmology's relationship to elementary particle physics. This work also includes a non-technical discussion of inflationary cosmology for those unfamiliar with the theory.

The publication of this book is extremely timely, for the next major advances in manned space flight after Project Apollo will most likely be made in earth orbital operations. Manned exploration of the moon will certainly continue after the initial landing, but it will be performed essentially with the Saturn V launch vehicles and Apollo spacecraft developed in Apollo, especially in the early phases. Modifications to this basic hardware will increase operating capabilities to permit extensive lunar explo ration during prolonged stay times by the astronauts on the moon's surface. Manned orbital space stations have been studied for years, and NASA is already well along in development of its first attempt to provide more spacious accommo dations for astronaut-scientists in its Saturn Workshop program. While the Workshop is certainly not the ultimate space station of which our technology is capable, it is a workable, poor man's approach to the immediate need for using and expanding our present manned space flight capability without a de trimentalloss of momentum. The approach of converting a Saturn rocket stage into a manned laboratory and observatory in space is an improvisation that matches the use of the jerry-built Jupiter C back in 1958 to launch Explorer I. Let's hope that it can get the job done just as effectively.

Energy, chemistry, solvents, and habitats - the basic elements of living systems - define the opportunities and limitations for life on other worlds. This class-tested text examines each of these parameters in crucial depth and makes the argument that life forms we would recognize may be more common in our solar system than many assume. It also considers, however, exotic forms of life that would not have to rely on carbon as basic chemical element, solar energy as a main energy source, or water as primary solvent. Finally the question of detecting bio- and geosignature of such life forms is discussed, ranging from Earth environments to deep space. While speculative considerations in this emerging field of science cannot be avoided, the authors have tried to present their study with the breadth and seriousness that a scientific approach to this issue requires. They seek an operational definition of life and investigate the realm of possibilities that nature offers to realize this very special state of matter and avoid scientific jargon wherever possible to make this intrinsically interdisciplinary subject understandable to a broad range of readers.

The second edition thoroughly updates this text in view of the rapid progress in the field and a substantial amount of new material has been added, in particular sections and chapters on adaptation to extreme environments, the future and fate of living systems, life detection concepts based on the thorough analysis of the Viking missions and the issue around the meteorite ALH 84001, and - last but not least - recommendations for the optimization of future space exploration missions.

From the reviews of the first edition:

" ...] I know of no other book that reassesses the fundamentals of astrobiology in such way. This book is a tacit lesson in open-mindedness tempered with thorough scientific analysis. This is a very important book for all professional astrobiologists." A Ellery, International Journal of Astrobiology, 6 (2007) 182-183

Throughout history people have sought ways in which to map the heavens. From the sources of mathematics and mythology sprang the classic star chart, the finest examples of which are both scientific documents and works of art. In this beautifully illustrated book, Peter Whitfield reveals some of the ways in which the structure of the universe has been conceived, explained and depicted. With examples ranging from the Stone Age to the Space Age - ancient observatories, the angelic visions of Dante, images from the Copernican revolution, the rationalized heavens of Isaac Newton, and modern deep space technology - Whitfield offers a challenging exploration of the tension between rigorous scientific knowledge and the continuing search for cause, certainty and harmony in the universe. This new edition is updated to include a wider range of stunning maps of the skies in full colour, including imagery from the latest voyages of space exploration.

The system of numbering the years A.D. (Anni Domini, Years of the Lord) originated with Dionysius Exiguus. Dionysius drafted a 95-year table of dates for Easter beginning with the year 532 A.D. Why Dionysius chose the year that he did to number as '1' has been a source of controversy and speculation for almost 1500 years. According to the Gospel of Luke (3.1; 3.23), Jesus was baptized in the 15th year of the emperor Tiberius and was about 30 years old at the time. The 15th year of Tiberius was A.D. 29. If Jesus was 30 years old in A.D. 29, then he was born in the year that we call 2 B.C. Most ancient authorities dated the Nativity accordingly.
Alden Mosshammer provides the first comprehensive study of early Christian methods for calculating the date of Easter to have appeared in English in more than one hundred years. He offers an entirely new history of those methods, both Latin and Greek, from the earliest such calculations in the late second century until the emergence of the Byzantine era in the seventh century. From this history, Mosshammer draws the fresh hypothesis that Dionysius did not calculate or otherwise invent a new date for the birth of Jesus, instead adopting a date that was already well established in the Greek church. Mosshammer offers compelling new conclusions on the origins of the Christian era, drawing upon evidence found in the fragments of Julius Africanus, of Panodorus of Alexandria, and in the traditions of the Armenian church.

The Theory Institute in Solar-Terrestrial Physics was held at Boston College 19-26 August 1982. The program consisted of a two-week School followed by the first theory conference in the field. This book is based upon the lectures presented at the School. Several years ago there was a convergence of efforts to promote the role of theory in space plasma physics. Reports from the National Academy of Sciences and NASA advisory committees documented the disciplinary maturity of solar-terrestrial physics and recommended that theorists play a greater role in the continued development of the field. The so-called theory program in solar-terrestrial physics was established by NASA in 1979 and implemented in accordance with the guidelines set forth by a panel of scientists, primarily theorists, in the field. The same panel motivated the Boston College program. Published proceedings of the school would provide curricular materials for the training of graduate students in solar-terrestrial physics. J.M. Forbes, T.E. Holzer, A.J. Hundhausen, A.D. Richmond, and G.L. Siscoe were the principal architects of the curriculum of the School, and I am grateful for their contributions. Each also lectured at the School. The chapters in this book were prepared by the authors themselves with one exception. The chapters by Parker are edited reproductions of his lectures. Unfortunately, it is our loss that the lectures of Holzer and Hundhausen are not included in the book.

This is volume 5 of Planets, Stars and Stellar Systems, a six-volume compendium of modern astronomical research, covering subjects of key interest to the main fields of contemporary astronomy. This volume on Galactic Structure and Stellar Populations, edited by Gerard F. Gilmore, presents accessible review chapters on Stellar Populations, Chemical Abundances as Population Tracers, Metal-Poor Stars and the Chemical Enrichment of the Universe, The Stellar and Sub-Stellar Initial Mass Function of Simple and Composite Populations, The Galactic Nucleus, The Galactic Bulge, Open Clusters and Their Role in the Galaxy, Star Counts and the Nature of Galactic Thick Disk, The Infrared Galaxy, Interstellar PAHs and Dust, Galactic Neutral Hydrogen, High-Velocity Clouds, Magnetic Fields in Galaxies, Astrophysics of Galactic Charged Cosmic Rays, Gamma-Ray Emission of Supernova Remnants and the Origin of Galactic Cosmic Rays, Galactic Distance Scales, Globular Cluster Dynamical Evolution, Dynamics of Disks and Warps, Mass Distribution and Rotation Curve in the Galaxy, Dark Matter in the GalacticDwarf Spheroidal Satellites, and History of Dark Matter in Galaxies.

All chapters of the handbook were written by practicing professionals. They include sufficient background material and references to the current literature to allow readers to learn enough about a specialty within astronomy, astrophysics and cosmology to get started on their own practical research projects. In the spirit of the series Stars and Stellar Systems published by Chicago University Press in the 1960s and 1970s, each chapter of Planets, Stars and Stellar Systems can stand on its own as a fundamental review of its respective sub-discipline, and each volume can be used as a textbook or recommended reference work for advanced undergraduate or postgraduate courses. Advanced students and professional astronomers in their roles as both lecturers and researchers will welcome Planets, Stars and Stellar Systems as a comprehensive and pedagogical reference work on astronomy, astrophysics and cosmology.

Bad Hofgastein who made the very successful Salzburger Abend with indi- nous music from Salzburg possible. Special thanks also to the former director of the Institute of Astronomy in Vienna, Prof. Paul Jackson for his generous private donation. We should not forget our hosts Mr. and Mrs. Winkler and their employees from the hotel who made the stay quite enjoyable. None of us will forget the very last evening, when the staff of kitchen under the le- ership of the cook himself came to offer us as farewell the famous Salzburger Nockerln, a traditional Austrian dessert. Everyone got a lot of scienti?c input during the lectures and the discussions and, to summarize, we all had a spl- did week in Salzburg in the Hotel Winkler. We all hope to come again in 2008 to discuss new results and new perspectives on a high level scienti?c standard in the Gasteinertal. Rudolf Dvorak and Sylvio Ferraz-Mello Celestial Mechanics and Dynamical Astronomy (2005) 92:1-18 (c) Springer 2005 DOI 10. 1007/s10569-005-3314-7 FROM ASTROMETRY TO CELESTIAL MECHANICS: ORBIT DETERMINATION WITH VERY SHORT ARCS (Heinrich K. Eichhorn Memorial Lecture) 1 2 ? ' ANDREA MILANI and ZORAN KNEZEVIC 1 Department of Mathematics, University of Pisa, via Buonarroti 2, 56127 Pisa, Italy, e-mail: milani@dm. unipi. it 2 Astronomical Observatory, Volgina 7, 11160 Belgrade 74, Serbia and Montenegro, e-mail: zoran@aob. bg. ac.

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."

This book is a history of the development of mathematical astronomy in China, from the late third century BCE, to the early 3rd century CE - a period often referred to as 'early imperial China'. It narrates the changes in ways of understanding the movements of the heavens and the heavenly bodies that took place during those four and a half centuries, and tells the stories of the institutions and individuals involved in those changes. It gives clear explanations of technical practice in observation, instrumentation, and calculation, and the steady accumulation of data over many years - but it centres on the activity of the individual human beings who observed the heavens, recorded what they saw, and made calculations to analyse and eventually make predictions about the motions of the celestial bodies. It is these individuals, their observations, their calculations, and the words they left to us that provide the narrative thread that runs through this work. Throughout the book, the author gives clear translations of original material that allow the reader direct access to what the people in this book said about themselves and what they tried to do.