jrasc june 1998 final - The Royal Astronomical Society of Canada

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jrasc june 1998 final - The Royal Astronomical Society of Canada

familiar. Never lose sight of the fact that some people find doingthings like income taxes, brain surgery or going to Edmontoneasy. Before you know it, you too will be learning the ancientincantations, the same ones used with little success to wardoff clouds by observers around the globe. You may never haveto learn how to calculate semi-conducting, non-existential,hyperbolic orbital curves; however you can easily learn how topoke around the dark night sky and catch a glimpse of the sameuniverse that holds most of us spellbound.Tom Cameron got his first Sears Discoverer telescope at age elevenwhile growing up in the shadow of Mount Kobau. His interest instargazing waned a few years later, but was rekindled in 1991 withthe purchase of a Celestron C4.5. He has been a member of theCalgary Centre for the last five-years, and gets out three or fourtimes each month to observe. Writing about his experiences landedhim a job as editor of the Calgary Centre’s newsletter; he also serveson the Centre’s council.Reviews of PublicationsCritiques d’ouvragesStars and their Spectra: anIntroduction to the SpectralSequence, by James B. Kaler, pagesxvi + 300; 17.5 24.5 cm, CambridgeUniversity Press, 1997. Price US$24.95.ISBN 0-521-58570-8Spectroscopy is one of theastronomer’s most usefultechniques, yet the popularpress rarely mentions the word. Thestudy of astronomical spectra providesa very powerful tool for astrophysical insight; if spectra werenot available, we would know very little about the universe andhow it works. The Hertzsprung Russell (HR) diagram, whichshows the relationship between spectra and absolute brightness,is one of the first and most notable examples of the use of ascatter plot in science, and contains a remarkable amount ofinformation about astrophysics. There is clearly a need for abook that explains how astronomers use spectroscopy and theHR diagram in terms that can be understood by the amateurastronomer or educated public. Kaler’s book fills the need well.I’m delighted to see this book in paperback finally. Thehardback edition was published in 1989 and was reviewed byChris Corbally in this journal (JRASC, 84, 358). The paperbackis a new printing, but not a new or revised edition. There is nopreface to indicate what changes have been made or whetheror not any sections have been updated; I suspect not. The onlyindication of any changes at all is on the copyright page, whichmerely states “(with corrections).” On the other hand, the bookis so well written that it remains an excellent book even as itwas written ten years ago.A preface would also be useful to indicate the targetreadership. The level is uneven. Some terms given withoutexplanations will mystify even the educated scientist; otherswill be much too simple for any reader. As far as I can tell, fewif any of the criticisms by reviewers of the 1989 edition havebeen addressed, which is a pity because it is a good book andcould be a great book.The opening chapter is an excellent summary of theinformation available about stars. It is followed by a very cleardiscussion of atoms, spectra and the spectral sequence. Themajor part of the book is a series of chapters discussing thecharacteristics of each type of star, beginning with the cooleststars, class M, progressing through the ranks to the hottest,class O. Peculiar stars are discussed along the way, but someextraordinary stars (e.g. central stars of planetary nebulae,interacting binaries, and supernovae) do not fit naturally intoany category, so they get a chapter of their own. In the lastchapter Kaler brings it all together with a romp through theHR diagram, tracing the paths of stellar evolution.I wish the author had given better references. The subjectis complex and the readership is likely to be at a high enoughlevel to want to know more. Kaler often does not give fullreferences, or even publication dates, rendering it unnecessarilydifficult for the curious to explore further. The intelligentamateur will want to read more. It also would be very helpfulto have some general references for further reading given atthe end of each chapter. This lack of proper references, evengeneral ones, detracts from the usefulness of the book, in myopinion.The reproduction of stellar spectra for illustrations is alost art, even for an experienced press like Cambridge. Manyof the illustrations are dark and contrasty, so it is difficult tosee some of the features referred to by the author. In addition,some of the illustrations taken from original papers have beencut up and pasted, which does not do justice to the symmetryand integrity of the original illustrations. Astronomers usenegatives or tracings in their work, so it would have been bestto illustrate them accordingly, in my opinion. This is not justa personal bias; negatives and tracings actually show the featuresbetter.164JRASC June/juin 1998

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