Review of David Levy’s Guide to Observing and Discovering Comets

A Comet Hunting Guide from a Master

David H. Levy is one astronomer who bridges the gap between science and the arts. One of the most successful comet hunters in history, he is pursuing a Ph.D. in literature at the Hebrew University of Jerusalem; a recent book of his is about how astronomy is presented in poetry. Several of his 29 books have been about comets, but David Levy’s Guide to Observing and Discovering Comets ($17.00, Cambridge University Press) is his first to go into detail about techniques to view and hunt them. It is an informative and fascinating book, peppered with anecdotes and literary references, that captures not only the nuts and bolts of comet hunting but also its spirit, as Levy tries to instill in the reader the joy and thrill of searching the night sky for these elusive objects.

Levy provides a history of cometary study, starting with the Roman writer Lucius Seneca, who was put to death by his emperor, Nero. Seneca’s writings are a compelling look into early thinking about comets. Levy includes brief biographies of many of the most notable comet hunters: Charles Messier, who in 18th-century Paris became the first to systematically hunt for comets by telescope; Jean-Louis Pons, Messier’s “successor”, whose 26 comets is second only to Carolyn Shoemaker on the all-time list; Caroline Herschel, the comet hunter in a family of famous astronomers; William R. Brooks and Edward Emerson Barnard, rival American comet hunters in the late 1800s (Brooks, an upstate New Yorker, is tied with Levy for third among comet hunters with 21); and various 20th-century comet hunters in America, Japan, Europe, and Canada. Levy tells how a colleague of Barnard’s had perpetrated a hoax by convincing a San Francisco newspaper that Barnard had devised an automated telescope that would track down comets while he was asleep, and set off an alarm when it found one. It took two years for Barnard to prove to the paper that they had been deceived and get them to print a retraction.

Levy has extensive experience in hunting comets visually, photographically, and electronically through CCD imaging, and he provides a detailed account of his work with each of these methods. He started visual comet hunting in 1965, and found his first in 1984, after 917 hours of searching. By 1989 that year he joined Gene and Carolyn Shoemaker in photographically searching for comets with an 18-inch telescope at Mt. Palomar. Among the comets he co-discovered with the Shoemakers was Shoemaker-Levy 9, which collided with Jupiter in 1994. Although he hasn’t found a new comet in almost a decade, he still regularly hunts for comets both visually and as part of a CCD project to find comets and asteroids—the Jarnac Sky Survey—he conducts with his wife, Wendee.

The book includes pointers on how to find comets by each of these methods (and how to report a suspected comet), as well as a section on finding SOHO comets that includes pointers by several of the most successful SOHO comet hunters. Levy also details his efforts to try to find a comet “on paper”. Clyde Tombaugh, discoverer of Pluto, had told Levy of a comet he had detected, but never reported, in Lowell Observatory images in the 1930s. Levy searched Lowell’s photo archives, and found three images of the comet from January 1931. For an orbit to be calculated and it to be officially recognized as a comet, more images need to be found, and Levy has searched other observatory archives, and even published an article on the object in an effort to find more images, so far without success.

Levy reflects on the future of visual comet hunting. Despite the encroachment by professional sky surveys, which will make amateur comet hunting all the more difficult as time goes by, he believes there will always be comets for amateurs to find visually, though it may take decades for some searchers to find one. He thinks that amateur CCD sky surveys, which found two comets in 2002, will continue to be fruitful.

The book also has detailed instructions for people interested in observing comets, drawing and photographing them, and measuring their size and magnitude. There is an appendix consisting of Levy’s list of 220 “comet masqueraders and other interesting objects”. It contains some Messier objects but also many less-well-known objects; those that look particularly cometlike are marked with an asterisk.

I noticed two errors in the text. On page 39, Levy blends the description of the Great Comet of 1882 with that of another bright comet seen the previous year, as if they were the same object—a particularly surprising error as the 1882 comet is especially famous, in fact the brightest comet on record. On page 81, he incorrectly states that XingMing Zhou uses a 6-inch reflecting telescope to search for SOHO comets. (Zhou does use such a telescope, but to hunt for comets in the night sky.) Nonetheless, these errors do little to detract from a lucid, comprehensive, and inspiring handbook for amateurs interested in conducting their own comet searches.

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