Video Astronomy

S. Massey, T.A. Dobbins and E.J. Douglass

Sky Publishing Corporation, 2000 – ISBN 0-933346-96-4 – pp.xii + 200 – $24.95 (paperback)

Reviewed by A.J. Elliott : Journal of the British Astronomical Association, 111 (5), 294 (2001)

Video Astronomy is the latest Sky and Telescope ‘Observer’s Guide’. These practical guides are written by authoritative and experienced observers with impressive credentials, and this book is no exception. It takes a detailed look at the equipment and techniques available for video-recording astronomical subjects.

While amateur astronomers cultivated an interest in integrating CCD cameras, real-time video technology was developing in parallel. Ten of the book’s sixteen chapters are devoted to the technical aspects of using video for astronomy – how video cameras work, choosing and using cameras, recorders and associated equipment, and methods of attachment to telescopes. The authors have researched these topics in depth, and explain the pros and cons of the various types of camera – analogue and digital camcorders, webcams, security-type cameras, and dedicated astronomical cameras such as SBIG STV. Camera prices range from tens to thousands of pounds, but good-quality video of the brighter objects can be obtained with cheaper instruments. It is therefore easy to start with an inexpensive system and upgrade later. One chapter covers linking cameras to PCs for capturing individual frames and real-time video, although this is a rapidly developing field which could merit a separate book.

The remaining chapters cover specific applications such as recording the Sun, Moon, planets, occultations, eclipses, transits, deep-sky objects, and meteors. Video cameras will never surpass integrating CCDs for imaging deep-sky objects, and the authors describe the use of a video camera as a guidescope for the latter. (Paradoxically, they also describe ‘spectacular’ images of deep-sky objects obtainable with an image intensifier and sensitive CCD camera in light-polluted skies. However, this is not the reviewer’s experience, and the only illustration included appears to be simulated.)

The book is profusely illustrated with pictures of equipment and screen shots of actual video. Although the images are, of necessity, rather small, they well illustrate the high quality that video is capable of producing. The authors point out that video rates of 25–30 frames per second allow compositing of ‘best seeing’ frames much more efficiently than for photography or CCD imaging. The down side is that most videos have only an 8-bit dynamic range, and therefore cannot match the resolution and quality of integrating CCDs. Nevertheless, the book amply illustrates the remarkable quality that can be achieved by video-processing on a PC. The reader should be aware, however, that the authors had access to professional telescopes and facilities. Some of their images – such as those showing surface markings on Ganymede, and the spectacularly detailed images of the Space Shuttle and the ISS flying overhead – will not be readily reproduced by most amateurs!

While CCD video cameras are unlikely to challenge integrating CCD systems for still images, they are nevertheless excellent at what they do best: recording dynamic events. Usable scientific data can be obtained, particularly for occultations and meteor work, although some applications require additional equipment such as an image intensifier and time inserter. Apart from scientific data acquisition, astronomical video recording has great educational potential. To watch seeing effects rippling over the Moon’s craters, occultations, and recorded meteor trails on a TV screen, really brings home the full sense of ‘being there’ to enthusiastic audiences.

This book is up-to-date to the point of publication, and includes images of the 1999 Leonid meteor impacts on the Moon. However, the field continues to develop, and even more sensitive and cheaper cameras are now available. The book is aimed at amateurs at all levels, but professionals may find much useful background information. The appendices detail further reading lists and a list of equipment suppliers. The book is biased towards North American readers, but it is not difficult to translate this to the British perspective.

Despite the occasional flowery prose, this reviewer can identify with the ‘gee whiz’ enthusiasm of the authors. This highly readable book presents a comprehensive and thorough introduction to the subject of video astronomy.