First published in 1958, this book examines the Galactic System in the light of then-recent developments in radio astronomy.

This book is the first thorough and overdue biography of one of the giants of science in the twentieth century, Jan Hendrik Oort. His fundamental contributions had a lasting effect on the development of our insight and a profound influence on the international organization and cooperation in his area of science and on the efforts and contribution of his native country. This book aims at describing Oort's life and works in the context of the development of his branch of science and as a tribute to a great scientist in a broader sense. The astronomer Jan Hendrik Oort from the Netherlands was founder of studies of the structure and dynamics of the Milky Way Galaxy, initiator of radioastronomy and the European Southern Observatory, and an important contributor to many areas of astronomy, from the study of comets to the universe on the largest scales.

The Andromeda Galaxy – Messier’s M31 – has an almost romantic appeal. It is the most distant object and the only extragalactic object that is visible to the unaided human eye. Now known to be about 21⁄2 million light-years away, it appears in the sky to be several times the width of the full Moon under good seeing conditions. The Andromeda Galaxy and the Rise of Modern Astronomy examines the astronomical studies of Andromeda and its importance to our developing knowledge of the universe. The book discusses how M31 was described both by the Ancients, but more importantly, by astronomers from the nineteenth century to the present. While at the start of the twentieth century the universe was thought of as a finite cosmos dominated by the Milky Way, the study of Andromeda galaxy shattered that image, leading ultimately to the conception of an infinite universe of countless galaxies and vast distances. Even today, M31 is a major focal point for new astronomical discoveries, and it also remains one of the most popular (and rewarding) celestial objects for amateur astronomers to observe and study. This book reveals the little-known history of M31 and the scientists who study it. For all who are interested in astronomy, the skies, and perhaps even the origins of the universe, The Andromeda Galaxy and the Rise of Modern Astronomy provides a first-of-its-kind accessible, informative, and highly readable account of how the study and observation of this celestial object has driven the development of astronomy from ancient times to the present.

This book is an outgrowth of the notes made for the semester lectures on 'Problems of Extragalactic Astronomy' given almost annually during two decades at the Ob servatorio Astronomico of the Universidad de Cordoba. Shorter versions were also given at La Plata, Santiago de Chile, Sao Paulo, Rio de Janeiro and Paraiba. E. Scalise made a Portuguese language version of the notes and encouraged me to publish them; although my friend J. Kleczek is to be blamed for the idea of this book. Not every subject on Extragalactic Astronomy has been touched in this book: instead I have followed those which interested me during 25 years of professional practice in this part of the world. I acknowledge helpful suggestions from M. Pastoriza and G. Carranza, the com prehension of Director L. Milone, and the collaboration of the staff of the Observa tory in Cordoba. R. Tschamler's humor and wit made light the task of producing the English version and M. Pizarro's devotedness produced the edited MS. To both of them I am in deep gratitude. "A book is published out of necessity, otherwise the author would spend his entire life polishing the originals" was the answer given by J.L. Borges to an inquisi tive journalist. These words explain why this book is so different from the lecture notes, and also from the book I was hoping for. I thank B. McCormac and the D. Reidel Publ. Co. for my salvation from Borges' inferno.

Interstellar matter is one of the most active fields of research in present-day astronomy. Observational information spans the full electromagnetic spectrum from gamma rays through rocket-ultraviolet, optical, infrared and millimeter to long radio waves. Results of research in physical chemistry find as much application as mathematical methods. Interstellar matter plays a leading role in studies of our Galaxy and of external galaxies, and contributes increasingly to stellar astronomy. At the 16th General Assembly of the International Astronomical Union, held in August 1976 in Grenoble, France, the many new developments in this vast field were surveyed in a number of sessions of Commission 34 (Interstellar Matter), mostly jointly with other Commissions of the Union. Separate sessions were devoted to: The hot interstellar gas phase, Interaction of stars and interstellar medium, Interstellar molecules and dust, The large-scale distribution of interstellar matter in the Galaxy, and Interstellar matter in external galaxies. Twenty-four invited review papers were presented and discussed in these sessions. The quality and success of these topical reviews made it seem desirable to make them available to a wider audience. Professor Edith Muller, the new General Secretary of the IAU, enthusiastically supported the idea. Most importantly, the reviewers - who had originally been pro mised that an oral paper was the only requirement - agreed to prepare written versions. I am grateful to Mrs. Muller, to the authors, and to Reidel Publishing for their collaboration in the preparation of this book.

Although less well known outside the field than Edwin Hubble, Walter Baade was arguably the most influential observational astronomer of the twentieth century. Written by a fellow astronomer deeply familiar with Baade and his work, this is the first biography of this major figure in American astronomy. In it, Donald Osterbrock suggests that Baade's greatest contribution to astrophysics was not, as is often contended, his revision of Hubble's distance and age scales for the universe. Rather, it was his discovery of two distinct stellar populations: old and young stars. This discovery opened wide the previously marginal fields of stellar and galactic evolution--research areas that would be among the most fertile and exciting in all of astrophysics for decades to come. Baade was born, educated, and gained his early research experience in Germany. He came to the United States in 1931 as a staff member of Mount Wilson Observatory, which housed the world's largest telescope. There, he pioneered research on supernovae. With the 100-inch telescope, he studied globular clusters and the structure of the Milky Way, every step leading him closer to the population concept he discovered during the wartime years, when the skies of southern California were briefly darkened. Most Mount Wilson astronomers were working on weapons-development crash programs devoted to bringing Baade's native country to its knees, while he, formally an enemy alien in their midst, was confined to Los Angeles County but had almost unlimited use of the most powerful telescope in the world. After his great discovery, Baade continued his research with the new 200-inch telescope at Palomar. Always respected and well liked, he became even more famous among astronomers as they shifted their research to the fields he had opened. Publicity-shy and seemingly unconcerned with publication, however, Baade's celebrity remained largely within the field. This accomplished biography at last introduces Baade--and his important work--to a wider public, including the newest generation of skywatchers.

This open access book is a biography of Joseph L. Pawsey. It examines not only his life but the birth and growth of the field of radio astronomy and the state of science itself in twentieth century Australia. The book explains how an isolated continent with limited resources grew to be one of the leaders in the study of radio astronomy and the design of instruments to do so. Pawsey made a name for himself in the international astronomy community within a decade after WWII and coined the term radio astronomy. His most valuable talent was his ability to recruit and support bright young scientists who became the technical and methodological innovators of the era, building new telescopes from the Mills Cross and Chris (Christiansen) Cross to the Parkes radio telescope. The development of aperture synthesis and the controversy surrounding the cosmological interpretation of the first major survey which resulted in the Sydney research group's disagreements with Nobel laureate Martin Ryle play major roles in this story. This book also shows the connections among prominent astronomers like Oort, Minkowski, Baade, Struve, famous scientists in the UK such as J.A. Ratcliffe, Edward Appleton and Henry Tizard, and the engineers and physicists in Australia who helped develop the field of radio astronomy. Pawsey was appointed the second Director of the National Radio Astronomy Observatory (Green Bank, West Virginia) in October 1961; he died in Sydney at the age of 54 in late November 1962. Upper level students, scientists and historians of astronomy and technology will find the information, much of it from primary sources, relevant to any study of Joseph L. Pawsey or radio astronomy. This open access book includes a Foreword by Woodruff T. Sullivan II.