insidethisissue - The Royal Astronomical Society of Canada

jargon to confuse the beginner. More importantly, I believe itallows the novice to cultivate an appreciation for planetarystudy. Should it be the sole source for planetary observingin your library? I would have to say no, since there are morecomprehensivebooks available, but it does earn a place on mybookshelf to supplement my collection.Mike KarakasMike Karakas is an Architectural Technologist by professionand planetary observing enthusiast by choice. He disregardsthe comments from his fellow astronomy friends who say thatplanets are light pollution, and enjoys both sketching and imagingplanets from his backyard in Winnipeg, Manitoba.The Telescope: Its History, Technologyand Future, by Geoff Andersen, pages 248;16.5 cm 24.5 cm, Princeton UniversityPress, 2007. Price $29.95 US hardcover(ISBN-13: 978-0-691-12979-1).Inspired by the upcoming 400th anniversaryof the invention of the telescope, GeoffAndersen has set out to write an ambitiousbook on the subject. Any of the aspects of telescopes mentionedin the subtitle — “its history, technology and future” — couldbecome the subject of a separate book, or even a series of texts.As if that were not enough, Andersen also wants to addressthe entire range of telescope usage, from department store toytelescopes used for casual stargazing, right up to our flagshipprofessional optical instruments, and even to address militaryapplications that reach to the barrier of state secrets. The goalsand scope (pardon the pun) of his effort are breathtaking, andleave the reader with great expectations.For the sake of general reader accessibility, Andersen hasalso restricted his use of mathematical formulae and technicaldescriptions. To help the reader explore some of the issuesmore thoroughly, he has included several appendices to aid theuninitiated in understanding concepts and terminology used inastronomy and other telescope applications. He also providesan introduction that coaches the reader to treat each chapterindependently so that a front-to-back reading of the book isnot required. The book is intended for those unfamiliar withtelescopes, and yet will provide veteran telescope enthusiastswith some new insights.The first two chapters give the reader an historicalintroduction to the development of telescopes, starting fromunaided-eye observations and the first telescopes pointedtoward the sky by Galileo. Several major figures in astronomy(Brahe, Kepler, and Newton) are included in the brief historylesson of astronomy during that period of discovery. If thereader is hoping for a more comprehensive history of telescopesof this period rather than astronomical advances, there willbe disappointment. Other than a comparison of the originalGalilean telescope with modern department-store refractors,there is little description of the instruments of that period or theeras that followed. No mention is made of the odd and unwieldyattempts by Huygens, Hevelius, and others to overcome thelimits of their technology with aerial telescopes and otherextreme long-focal-length refracting instruments. Althoughsome attention is given to the difference between Galilean andastronomical telescopes in a later section on how telescopeswork, no mention of Kepler or Christoph Scheiner is made indocumenting technological improvements to refractors of thisearly period. Similarly, while the reflector designs of Gregoryand Cassegrain are talked about in later chapters, their place inthe historical development of the instrument is left out. Otheromissions include the contributions by Chester Hall, JosephFraunhofer, and more modern opticians, such as BernhardSchmidt, Dmitri Maksutov, and Joseph Petzval, all of whomhave made significant contributions to modern telescopedesign. Moreover, could any historical account of telescopesbe adequate without the mention of the Herschels (William,Caroline, and John)? So the history of the telescope is given shortshrift. That might be agreeable to readers who are looking for abroader and more digestible perspective, but it is a pity, sinceAndersen’s style would have made for a good version of thismore technologically oriented and much overlooked history.Andersen does an admirable job of conveying the basicsof telescopes to the reader in chapters three through five. Hisaccounts of diffraction and telescope aberrations are veryunderstandable, especially the italicized description of Airydiscs and just what a perfect image affected by diffraction wouldlook like. And yet, all accounts, including Andersen’s, could stilluse some forceful explanations emphasizing that an Airy discis also the result of “perfect focus” to drive home the point thattelescopes do not render stars as “points.”When it comes to expressing the technological aspectsof modern telescopes, Andersen gives us a broad andcomprehensive account that takes the reader into applicationsthat one does not normally associate with telescopes. Mostreaders having some familiarity with optics might be acquaintedwith interferometry, but Andersen’s clear account will advancethat understanding and extend it in ways not considered. Thosenew to the subject might find the section daunting. Andersenalso takes the reader on a whirlwind tour of unconventional usesof telescopes, including military and intelligence applications,another subject that is much overlooked in most accounts.One odd chapter is entitled suggestively, “So you want tobuild an observatory?” Despite the title, he has little to say aboutthe practical considerations of building an observatory. Instead,he gives us a cursory rundown of the considerations that haveto be dealt with in the construction and location of world-classresearch facilities. Again, the material presented, while relevantto the topic, is not quite in accord with the chapter title andApril / Avril 2008JRASCBuilding for the International Year of Astronomy (IYA2009)83

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