Comets and How to Observe Them Author: Richard Schmude Publisher: Springer ISBN: 978-1-4419-5789-4 Price: £31.99 (Pb), 254pp
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Richard Schmude’s passion for astronomy, and the chemistry of comets in particular, brings to the table a book that covers almost every point in the comet observer’s arsenal. Kicking off with an overview of standard naming nomenclature, he deftly moves into a review of the laws of orbital mechanics, without diving too deeply into the mathematics, and in a way in that everyone should easily grasp. Sungrazers and short/long period comets are clearly explained, in terms of their physical and orbital characteristics, before a thorough overview of their chemical and physical composition and how their characteristic tails are formed.

Recent impact events observed by amateurs also give this book a down to earth and contemporary feel, before launching into a detailed analysis of several more famous cometary encounters, including a personal favourite in the Deep Impact mission to Tempel 1. In these sections, Schmude does dive into some heavier treatments of comet structure, composition and orbital data, but then brings it back into perspective with wonderful analogies with known objects. He does this not only for Tempel 1, but also Halley, Wild 2 and Borrelly, but stick with it, you’ll learn a lot!

Moving onto visual observations, Schmude covers a topic close to my heart, one of brightness and magnitude estimation. After the recent 103P debacle where visual and photometric measurements were showing wild fluctuations in magnitude values, this is a very good treatise and explanation as to why that happened. The almost obligatory overview of telescopes/seeing and optics then fills up a good few pages. What was surprisingly missing was a lack of discussion of in-depth imaging methods, in particular the use of things like rotational gradient processing (admittedly a potentially risky technique if not used correctly) for examination of the tail/inner coma and for assisting in measuring things like rotation speed, successfully done recently on 103P by many amateurs. In fact imaging, apart from a few well presented examples, gets short shrift in this book.

The book is satisfying in many ways, filling in gaps in my knowledge in a way that kept me reading, despite the plethora of equations and values, but ultimately it left me wanting more. That said it is a very useful companion to any comet observer, and one that should find its way into the library of any university course or student of these most magical cosmic interlopers. A recommended read indeed, but one in which I hope a second edition covers more of the art and science of imaging.

Nick Howes