Astronomical Spectroscopy for Amateurs
Submitted: Friday, 25th March 2011 by Al Sheehan
I’ve just finished reading my copy of Ken’s new book “Astronomical Spectroscopy for Amateurs” (ISBN 978-1-4419-7238-5) and I must say our Ken (Merlin66) has done a great job! Published by Springer as part of Patrick Moore’s Practical Astronomy Series, this is an excellent guide and reference for the amateur astronomer active or just interested in spectroscopy.
Ken has taken a slightly different approach to many other texts on spectroscopy: a very low key, plain English delivery of enough theory and practical skills to get someone from, say, basic astronomy skill level to producing meaningful spectra. It’s not heavy duty reading.
One of the tricks that Ken has used in the book to keep it simple and help it work the way its intended to is to include a “Further Reading” section and a “Web Pages” section at the end of each chapter. So if you want to know more, you can go there, but if you don’t you don’t have to.
The book is divided into three parts, and as Ken claims in his Preface, each part stands well alone. It isn’t necessary to read the whole book, it works very well just reading what you want to know now (assuming you have the basics I guess).
Part one is an introduction to spectroscopy. Logically, it starts with the history of spectroscopy to build the background and big picture, before delving into the theory of spectroscopy. Don’t be alarmed by the use of the words “theory” and “spectroscopy” in the one sentence – its not so scary, at least it’s not the way Ken tells it! There are a few formulae, but you really don’t need to know these formulae to get started, and the diagrams in the book can convey the meaning of the formulae very clearly and easily. “Theory of Spectra” covers just 19 pages, but it is clear and concise, and nowhere near as daunting as some whole texts on the matter. If you eventually want to get into measuring and calculating redshifts, you can find the formula here later when you need it.
Part one concludes with discussions of different types of spectroscopes, from the humble prism to gratings and grisms, and the various ways they can be arranged to produce spectra.
Part two is really practical. “Obtaining and Analysing Spectra” is the down to earth practical advice on how to do it. Much of this is information is freely available on the web and from other books, but here it is all presented clearly, and concisely in a logical sequence. This part starts off discussing how to set up the spectroscope – full of practical tips.
Chapter 7 is all about “Spectroscopes in the Converging Beam” – that’s StarAnalyser 100 and Rainbow Optics 200 type transmission gratings typically, and the next chapter is about reflection grating spectroscopes – how to set them up and use them, followed by descriptions of most of the commercial spectroscopes that an amateur may encounter.
Chapter 9 discusses Cameras and CCD’s with respect to spectroscopy, but really it’s not so different to normal astrophotography.
Chapters 10 and 11 round out part two of the book with “Processing Spectra” and “Amateur Spectroscope Projects”.
“Processing Spectra” is really strong on how to use VSpec – the freeware that is the defacto standard for processing spectra. I’ve been using VSpec for quite a while now and still learned a few tricks from this chapter. To be critical though, the section on pre-processing was perhaps a little light on. IRIS is another freeware that is used for preprocessing the spectra, and it’s a command line or menu/dialog driven program rather than a WYSIWYG GUI, so it does take a little bit to get used to driving now that we’ve all become lazy using windows! Once you know how to do something in IRIS though, its very easy and it does it exceptionally well. The IRIS component of preprocessing a transmission grating spectrum (like you get from a StarAnalyser) is minimal, but the prepocessing gets a bit more involved when you start using a slit spectrograph. That’s what I’m starting to learn at the moment, so maybe that’s why I’d personally like to see more step by step preprocessing stuff in IRIS, to complement the excellent guidance through VSpec.
“Amateur Spectroscope Projects” discusses the various types of projects you could use your spectroscope for and the suitability of various spectroscopes for each project. This good guidance to help you choose a spectroscope if you have a particular interest, or to avoid frustration by adapting your projects to suit your spectroscope.
The final part of the book is titled “Spectroscope Design and Construction”. You may think that this only of interest if you are planning to design and build your own spectrograph, but that’s not entirely true. A lot of this stuff is handy to know to modify your spectroscope, or just to understand how it works so you can use it more effectively. The section on Guiding is valuable reading for any spectroscopist.
Illustrations throughout the book are clear and clean and most, if not all, spectra are the product of amateurs and excellent examples of what can be achieved.
The “Extras” is a nice touch. These are downloads that book purchasers can access from the Springer site including spreadsheets, the final illustration list, copies of VSpec and IRIS software and some spectroscopy presentations in Powerpoint and PDF form, and even a list of the webpage links from the book so you don’t have to type in the URLs!
From the extras page on the Springer site, there is also an online copy of the book and facility to download a PDF copy. Presumeably, this is so you can also read it on your eBook reader, however, I had a problem on my first download attempt and the security prevented me from downloading it again. The error message it gave me the second time was that it was “available to subscribers only” so perhaps you need to buy chapters of the book for download.
If you are interested in spectroscopy, then I recommend this book as an excellent starter. All but the most experienced astro-spectroscopists will get something new out of this book, or at least find it handy to have such a reference source all in the one place.