The Westerbork Observatory Continuing Adventure In Radio Astronomy

A small country builds a world-class telescope in its backyard and lives happily ever after (or at least for a quarter century). That in a nutshell is the story told in this collection of essays. The country of course is the Netherlands, and the telescope is the Westerbork Synthesis Radio Tele scope (WSRT), brainchild of Jan Oort. Living happily in this context is a continuing record of discovery and as such also a continuing basis for se curing observing time on facilities in other countries and operating at other frequencies. As our community celebrates the Silver Anniversary of the radio tele scope at Westerbork, it is fitting that we pause to take account of the scientific discoveries and insights it made possible. Initially the instrument represented the very significant step away from university-run, specialist facilities to a well-supported, common-user radio imager also having spec tral and polarization capabilities. It pioneered the mode of operation now common for satellite observatories, in which data is taken and calibrated by technicians and provided to researchers ready for analysis. It has been a major source of discovery in, among other areas, research on neutral hy drogen and studies of dark matter in galaxies.

Radio astronomy was born during the Second World War, but as this book explains, the history of early Dutch radio astronomy is in several respects rather anomalous in comparison to the development of radio astronomy in other countries. The author describes how these very differences led the Netherlands to become one of the world leaders in radio astronomy. Dominated by the Leiden astronomer Jan Hendrik Oort, the field embarked on an era of success, and to this day, the country still holds a leading position. To tell this story, the book focuses on three key events in the period 1940-1970, namely the construction of the radio telescopes in Kootwijk (1948), in Dwingeloo (1956), and in Westerbork (1970). These projects show that Dutch radio astronomers must not be seen as merely scientists, but also as strategic lobbyists, networkers and organizers in a specific political and economic context. It was in the process of planning, designing and constructing these instruments that the interests of the astronomers, industrial partners, politicians and lobby groups merged to create today's existing research centers for radio astronomy.

Radio Observatory and Telescope Index -- General Index

This book is open access under a CC BY-NC 4.0 license. The third edition of this indispensable book in radio interferometry provides extensive updates to the second edition, including results and technical advances from the past decade; discussion of arrays that now span the full range of the radio part of the electromagnetic spectrum observable from the ground, 10 MHz to 1 THz; an analysis of factors that affect array speed; and an expanded discussion of digital signal-processing techniques and of scintillation phenomena and the effects of atmospheric water vapor on image distortion, among many other topics. With its comprehensiveness and detailed exposition of all aspects of the theory and practice of radio interferometry and synthesis imaging, this book has established itself as a standard reference in the field. It begins with an overview of the basic principles of radio astronomy, a short history of the development of radio interferometry, and an elementary discussion of the operation of an interferometer. From this foundation, it delves into the underlying relationships of interferometry, sets forth the coordinate systems and parameters to describe synthesis imaging, and examines configurations of antennas for multielement synthesis arrays. Various aspects of the design and response of receiving systems are discussed, as well as the special requirements of very-long-baseline interferometry (VLBI), image reconstruction, and recent developments in image enhancement techniques and astrometric observations. Also discussed are propagation effects in the media between the source and the observer, and radio interference, factors that limit performance. Related techniques are introduced, including intensity interferometry, optical interferometry, lunar occultations, tracking of satellites in Earth orbit, interferometry for remote Earth sensing, and holographic measurements of antenna surfaces. This book will benefit anyone who is interested in radio interferometry techniques for astronomy, astrometry, geodesy, or electrical engineering.

This open access book on the history of the National Radio Astronomy Observatory covers the scientific discoveries and technical innovations of late 20th century radio astronomy with particular attention to the people and institutions involved. The authors have made extensive use of the NRAO Archives, which contain an unparalleled collection of documents pertaining to the history of radio astronomy, including the institutional records of NRAO as well as the personal papers of many of the pioneers of U.S. radio astronomy. Technical details and extensive citations to original sources are given in notes for the more technical readers, but are not required for an understanding of the body of the book. This book is intended for an audience ranging from interested lay readers to professional researchers studying the scientific, technical, political, and cultural development of a new science, and how it changed the course of 20th century astronomy.

Comprehensive, authoritative coverage of interferometric techniques for radio astronomy In this Second Edition of Interferometry and Synthesis in Radio Astronomy, three leading figures in the development of large imaging arrays, including very-long-baseline interferometry (VLBI), describe and explain the technology that provides images of the universe with an angular resolution as fine as 1/20,000 of an arcsecond. This comprehensive volume begins with a historical review followed by detailed coverage of the theory of interferometry and synthesis imaging, analysis of interferometer response, geometrical relationships, polarimetry, antennas, and arrays. Discussion of the receiving system continues with analysis of the response to signals and noise, analog design requirements, and digital signal processing. The authors detail special requirements of VLBI including atomic frequency standards, broadband recording systems, and antennas in orbit. Further major topics include: * Calibration of data and synthesis of images * Image enhancement using nonlinear algorithms * Techniques for astrometry and geodesy * Propagation in the neutral atmosphere and ionized media * Radio interference * Related techniques: intensity interferometry, moon occultations, antenna holography, and optical interferometry Interferometry and Synthesis in Radio Astronomy, Second Edition is comprehensive in that it provides an excellent overview of most radio astronomical instrumentation and techniques.

Enhanced sensitivity radio telescopes are producing dramatic results. An international conference was held in Jodrell Bank to take stock of these advances. This timely volume presents the review articles presented by a host of world experts who gathered at this meeting. We are shown how high sensitivity is advancing our understanding in radio spectral line analysis, radio continuum observations of galaxies, cosmology, pulsars, and radio emission from stars; what new and enhanced instruments are now available and those planned for the future. This volume provides graduate students and researchers with an up-to-date and wide-ranging review of the new and future research possible with high-sensitivity radio telescopes.