[.ca] Telescope Optics: Evaluation and Design (ISBN 0943396182)

Manual is more comprehensive than accessible:
There was a time once when amateur astronomers had exposure to only a few different kinds of telescopes--mostly simple achromatic refractors, which comprise just two lenses cemented together (plus an eyepiece), and Newtonian reflectors, which include a mirror plus the eyepiece. Many, possibly most, of these amateurs also made their own optics, and as a result, they knew most of what there was to know about these designs. Nowadays, it's quite different. Not only are there vastly more types of telescopes, but most amateurs now buy telescopes; telescope building is a diminishing part of amateur astronomy, and people make their own telescopes out of desire, not necessity. It's harder than ever now for amateurs to really know about optical designs in breadth and depth. Into this breach step Rutten and van Venrooij, two Dutch astronomers who wanted to know more about optics but found that resources were generally unavailable to amateurs. So, they wrote their own. Telescope Optics is a compendium of optical information, geared to the intermediate to advanced amateur. Like Gaul, it can be divided into three parts: Chapters 1 through 4 discuss optical principles; Chapters 5 through 16 apply those principles to various telescope and accessory designs; and Chapters 17 through 22 cover evaluation and design. The manner of the text is generally scholarly but informal. Although optical principles are explained from the fundamentals, the authors still assume a certain level of comfort with high school mathematics and analytical exposition. In particular, it helps if the reader can easily digest information in two-dimensional graphs. This can make the book somewhat imposing for those readers who really just want to know, at a high level, what makes their own telescope tick. For those readers capable of making their way through the analysis, however, the authors clearly and comprehensively explain the workings of several telescope and camera designs, and discuss in brief the quirks of at least half a dozen more. The compromises of each design are detailed to the level of so-called "third-order aberrations"; these include coma, astigmatism, field curvature, spherical aberration, and distortion. The authors also make available their own design software. Being 15 years down the line, the software is somewhat out of date, and it does not come free with the book; it must be purchased separately. The book does explain how to use the software, though. Overall, the book should find its way onto the shelf of anyone who wants to learn, seriously, about their optics. For those who simply want a taste of how optics work, or who need a gentle introduction to the field, it probably ought to wait until later.