Double Multiple Stars And How To Observe Them

Written specially for practical amateur astronomers who not only want to observe, but want to know and understand the details of exactly what they are looking at. Presents an up-to-date detailed description of the objects, their physics and their evolution (part one); and then (part two) to consider how to observe and record them successfully. Delivers a wealth of information for all levels of amateur observers, from the beginner to the experienced; it is equally fascinating for practical astronomers, and also for those who simply want to find out more about these unusual star systems.

Written specially for practical amateur astronomers who not only want to observe, but want to know and understand the details of exactly what they are looking at. Presents an up-to-date detailed description of the objects, their physics and their evolution (part one); and then (part two) to consider how to observe and record them successfully. Delivers a wealth of information for all levels of amateur observers, from the beginner to the experienced; it is equally fascinating for practical astronomers, and also for those who simply want to find out more about these unusual star systems.

From the reviews: "I recommend it to anyone with an interest in binary stars who wants to learn more about these fascinating objects." (Jocelyn Tomkin, The Observatory, April 2005)

Double & Multiple Stars, and How to Observe Them' is written specially for practical amateur astronomers who not only want to observe, but want to know and understand the details of exactly what they are looking at. It is a mine of information for all levels of amateur observers, from the beginner to the experienced.

"Observing Visual Double Stars, " written by an astronomer who has discovered almost 2,000 of them, opens the way to amateur astronomers who wish to make a direct and real contribution to science through their avocation.Double or binary stars--pairs of stars that revolve around one another--were once thought to be rare, anomalies among the vast number of normal, isolated stars, like our sun. Now, however, it is believed that many if not "most" stars are mated in binary systems. The visual binaries are those whose component stars are rather distant from each other and require decades or even centuries to complete their orbits. Few professional astronomers devote their time to making the observations needed, over these extended periods, to determine the characteristics of even a small sample of these systems. Thus, if any sizable number of double stars are to be closely scrutinized, their periodic variations plotted, and their orbits and masses calculated, the host of amateur astronomers will have to come to the aid of the professionals by making patient, systematic, night-after-night, year-after-year recorded observations."Observing Visual Double Stars" is designed to train amateurs to become such lookouts. After a historical account of the discovery of binaries (from the sighting of the first in 1650, through the work of the Herschels and the Struves in the eighteenth and nineteenth centuries, to the present), the author describes the various classes of telescopes and other instruments and the relevant optical principles. This is followed by practical advice on how to use this apparatus to identify double stars and measure their variations over time.The heart of the book--and its technically most advanced section--presents the mathematical techniques that will allow the observer to calculate orbits and masses from the variables that have been measured. A chapter entitled "Voyage to the Country of Double Stars" describes a binary system as it might appear to an observer within it. The book also explains the use of star catalogues and presents its own catalogue of 744 double stars accessible to the amateur observer.

Double and multiple stars are the rule in the stellar population, and single stars the minority, as the abundance of binary systems in the space surrounding the sun shows beyond doubt. Numerous stellar features, and methods of their exploration, ensue specifically from the one but widespread property, the binary nature. Stellar masses are basic quantities for the theory of stellar structure and evolution, and they are ob tained from binary-star orbits where they depend on the cube of observed parameters; this fact illustrates the significance of orbits as well as the accuracy requirements. Useful in dating stellar history is the knowledge that components of a system, different though they may appear, are of the same origin and age. Between star formation and the genesis of binaries a direct connection can be traced. The later stages of stellar life branch into a great variety as mutual influence between the components of a close binary pair develops. Transfer and exchange of mass and the presence of angular momentum in the orbit give rise to special tracks of evolution, not found for single stars, and to peculiar spectral groups. This is not a new story but it has a new ending: The patterns of evolution involving mass transfer appear to lead ultimately to single objects.

This workshop is devoted to Double stars. The general topics of the meeting were: for mation, dynamics and evolutionary tracks. In accordance with the pure tradition of the Saint James way, "pilgrims" from all over the world come to meet together in Santiago. Although with a common interest (double stars), this meeting was a multidisciplinary one, since scientists with different backgrounds participated in it. As a matter of fact, we think that this is the first workshop jointly supported by IAU Commissions 7 (Celestial mechanics) and 26 (Double and multiple stars). It is our belief that this meeting will be the origin of a more close relations and common research. This meeting was held under the invitation of the University of Santiago de Compostela to commemorate its fifth centenary, and organized by the Astronomical Observatory named after its founder, Ramon M. Aller, who made significant contributions in the study of visual double stars, and was one of the pioneers who put the seeds of the present blossoming of Astronomy in Spain. The Scientific Organizing Committee was formed by Drs. C. Allen, P. Couteau, J. A. Docobo, R. Dvorak, A. Elipe, S. Ferraz-Mello (co-chairman), H.A.McAlister, M. Valtonen, C.Worley (chairman) and H. Zinnecker. The Local Organizing Committee was formed by Drs. J. A. Docobo (chairman), A.

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