Customer Reviews

David Levy's Guide to Observing and Discovering Comets

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I bought this book by noted comet discover David Levy hoping that it would serve as a practical guide for amateur astronomers interested in observing and studying comets. Instead, this book is mostly about how Mr. Levy and his dedicated search team discover comets. If you're looking for advice on what type of telescope is best for observing comets (or maybe large binoculars are better?) you won't find it here. While Levy briefly mentions the telescopes he uses, there was no discussion of the equipment options available to the typical amateur astronomer on a budget (wide field refractors and reflectors, binoculars, etc.). The book also lacks advice regarding the weather conditions and locations that are best for observing comets - except to note that at one point Levy and his family moved to Arizona. That's great for them, but what about the rest of us who can't pack up our lives and move to the desert? The book is light on text and heavy on black and white images, many of which are grainy and provide little useful information. One of the more informative sections of the book is the explanation of the arcane new naming system for comets that was developed by the International Astronomical Union in the mid 1990s. There is also a brief discussion of the morphology of comets and the terminology used to describe the various components that can be seen visually. I would have liked this discussion to have been more detailed, perhaps citing various examples based on visual observations using amateur instruments. Levy devotes a large section of the book to his discovery of Comet Shoemaker-Levy, which collided with Jupiter in 1994. Although this is a significant achievement worthy of mention, its important to note that this comet was discovered using a large professional telescope the likes of which most amateurs will never be able to use. Levy also devotes considerable space to describing his experience searching for comets photographically, on old plates, and with CCDs, yet he gives short shrift to visual observation, which is relegated to the back of the book. As Levy correctly notes, the advent of inexpensive CCD cameras and remote telescope operation, combined with wide-field astrograph telescopes, has largely replaced visual sweeping as the main method of comet discovery. However, most readers of this book will probably not be engaged in comet discovery efforts, but will be using their eyes to search for known comets. It is this type of casual visual observer that the book largely lets down. Based on Mr. Levy's reputation as a dedicated and accomplished amateur observer, I was expecting a more comprehensive treatment of the subject that could serve both as a reference and as a practical guide at the eyepiece. Instead, I found this book to be mainly a recap of the notable achievements of the Levies and a few of their colleagues. Interesting, but not exactly a practical guide for the amateur.

David begins his book in an unsuspecting manner with a quick look back at how comets effected the lives of our ancestors; before the age of telescopes. Briefly, he demonstrates that comets were recognized by not only early scientist, but poets and "fallen princes."

His book is lightly peppered with people, events, and places of historical significance; e.g., that Edmond Halley "dropped out" from Oxford and "headed south that same year to the island of St. Helena, the island that, more than a century later, would serve as Napoleon's home after the battle of Waterloo."

He takes you on a journey through the discovery of comets (in which some cases, comets turn out to be planets - as was in the case of Uranus, Herschel 1781), the recovery of comets, and he discusses the ardent task of mathematically calculating orbits and estimating returns (it was Encke the "mathematician", not Pons "the astronomer", whose name lives on with the 3 1/3 yr. comet - Comet Encke).

He speaks of houses "made of comets." Actually, financed by comets for the honored American astronomer Bernard, who, with 2 months of formal education, paid his bills by discovering comets. You also hear the tales of morale boosting pranks that college fellows play on one another.

He continues on through the pain staking task of searching and searching, for hours on end, until after 917 hours and 28 minutes, spread out over 19 years, he discovered a comet. Correction, he co-discovered a comet. It was discovered simultaneously by another American astronomer. Very interesting to hear him tell the story.

David touches on systematic comet search techniques, tips on film, pros and cons of CCD (digital imaging and why film is better), the problem of staying focused, and how he breaks the sky down into a grid and methodically examines each point of light; twice! (per night...) How else can one detect *ever so slow-motion movement* of a very distant object?

Finally, David chronicles the discovery, predictions, and events leading up to the impact of Shoemaker-Levy 9 into Jupiter. Very enjoyable read.

P.S. The book has many pictures scattered throughout and has a nice set of color photos at the books center.