Moon Observer's Guide

Moon Observer’s Guide by Peter Grego Review by Thomas Watson click to email author

Disclaimer: the author of this review has no financial connection to the publisher of this work. The copy

file:///Users/asaint/cloudy/books/moon.htm (1 of 5)8/16/2004 8:33:52 AM Cloudy Nights Moon Observers Guide Copyright (C) 2004 Cloudy Nights Telescope Reviews reviewed was obtained through the University of Arizona Bookstore.

Our planet’s natural satellite is often the object of scorn by amateur astronomers who live for glimpses of deep sky objects. And, to be sure, when old Luna lights up the night, the faint fuzzies just cannot compete. Some us, unwilling to leave our telescopes idle in the corner of the living room for the duration of any given lunation, observe and study the Moon rather than surrender perfectly good observing time. And then there are those of us for whom the Moon is a marvelous opportunity, a chance to observe closely and in marvelous detail an alien world. For us, the Moon is the major motivation for being involved with astronomy in the first place.

Whatever your motive for observing the Moon, you will find no shortage of handbooks and manuals to guide you in your lunar explorations. A recent addition to the lunar bibliography is the Moon Observers Guide by British amateur astronomer Peter Grego. Originally published in the UK, the book appeared in American bookstores (published by Firefly Books) earlier this year (2004). It has a compact, sturdy paperback format with a size and shape that reminds many of us (on my side of the pond, anyway) of the old Golden Guide nature series. It runs a modest 192 pages, and carries a cover price of $14.95 US. With an attractive price like that, Grego’s Moon Observers Guide already stands out in the crowd, since so many of its counterparts are push forty or even fifty bucks (US).

Moon Observers Guide organizes the information you need to begin observing the Moon in seven sections:

1- Lunar Geology and the Moon's Features

2 - The Moon in Space

3 - The Lunar Observer's Equipment

4 - Moonwatching

5 - Recording Your Observations

6 - Eclipses and Occultations

7 - The Space Age Moon

Following an introduction that spells out the author’s interest in and motivation for studying the Moon (anyone who enjoys lunar observation will relate easily to his point-of-view, which is very nicely expressed), the reader is given a concise introduction to lunar geology, covering the major types of features such as the maria, craters, rilles, and mountains. The probable origins for each type are discussed, and prominent examples are given to illustrate the points being made. While thoroughly packed with information and very well written, the geology sections is weakened a bit by a shortage of

file:///Users/asaint/cloudy/books/moon.htm (2 of 5)8/16/2004 8:33:52 AM Cloudy Nights Moon Observers Guide Copyright (C) 2004 Cloudy Nights Telescope Reviews illustrations of the named features used as examples. Here the descriptive writing that is a characteristic of the entire book prevents a flaw from becoming a major problem. The prose is aided, in this case (and elsewhere in the book), by some nice illustrations of the geologic forces and mechanisms thought to be responsible for the formation of craters, rilles, and basins. The lack of photographs in this section is regrettable, but considering how much more expensive the book would have been if such had been included, I have trouble finding fault. There is no shortage of well-illustrated lunar atlases out there, and one thing they all have in common is price. Grego’s Moon Observers Guide is clearly designed to buck this trend by being an affordable introduction to the Moon.

The next section deals with the Moon as a body in space. Almost everything to do with the Moon orbiting the Earth - phases, libration, the path the Moon makes through the sky (but not, oddly enough, eclipses) - is explained in this section simply and concisely, with sufficient illustration to make things abundantly clear. A curious bonus in this section is his description of a Lunar cross staff, an instrument of measurement from the pre-telescope era, which can be used to prove the Moon illusion (the Moon looking larger as it rises than it does overhead) is just that, an illusion. (I was so intrigued by the mention of this pre-telescope astronomical instrument that I looked up more information on it, and plan to build one to try out for myself.)

What comes next is a section on telescopes, binoculars, eyepieces, and accessories for the observer of the Moon. I was prepared for material that was completely redundant, given how often such material is covered in more general manuals for backyard astronomers. And to a degree, this was so. But what this section of the book does well is aim the material at readers for whom the Moon is the reason they decided to buy a telescope in the first place. (Oddly enough, faint galaxies are not the only objects that attract people to astronomy.) The section on astro gear manages to remain relevant to lunar observing, and so avoids being completely redundant. There is a section on what to expect of various degrees of resolving power, relative to aperture, that is especially useful. In the chart on page 56, I was able to determine that my SVP 8EQ can resolve craters down to a size of 1.8 km. Useful stuff for those of us in the habit of planning an observing session. Everything from telescopes to software is briefly, but clearly, covered.

By this point you’ve gotten through roughly a third of the book. The middle third is the ‘atlas’ portion of the book, although perhaps I shouldn’t use the word atlas. The section entitled “Moonwatching” does contain maps with labeled featured, but it is more of a guide to what to look for, and when to look, than an exhaustive atlas. This is not a bad thing, and is in fact the single most useful feature of the book. What you have is a day-by-day tour of the Moon, with discussions of regions and their stand-out features as they are revealed by the terminator. The most useful aspect of this approach (not unique, to be sure) is that is allows the observer to plan a session according to what parts of the moon will show the best contrasts between light and shadow, casting features in the highest relief. Shadow and light are everything when studying the Moon. A feature that is clearly visible in the early morning (lunar local) sunshine can be all but invisible when the Moon is full. The lunar map sections drawn to depict new territory revealed each day of a lunation make it very easy to decide ahead of time when to go looking for a given feature. The text portion of this day-by-day tour is as clear and concise as the prose throughout the book.

Two things, however, detract from the “Moonwatching” section of the book. The first, the small size of the print used to label lunar features, is not the great handicap it might at first seem to be, because the labels stand out clearly against the maps - which are very nicely depicted - and there are no labels crowded together (a major problem for Cherrington’s Exploring the Moon Through Binoculars and Small Telescopes). They are, however, very small, and might be difficult to read in the low light levels likely to be used by an observer peering through the eyepiece of a telescope. I don’t consider this a major problem at all, since I recommend this book as a research and planning tool, not a scope-side resource. But if you are using this book on its own, while observing, consider keeping a magnifying glass handy.

The second detraction is more troublesome: not everything discussed in the text is actually labeled on the maps. Although most of the unlabeled features are discussed relative to features that are labeled, it isn’t always clear how far from a named crater one might find the feature under discussion. It seems to me that in the attempt to keep the lunar maps clear and useful, the labeling of features was given short shrift. To be fair, many of the features discussed but not labeled would be difficult to depict on the scale used for these maps, but in that case I would favor leaving them out of the discussion altogether (or illustrating them with the occasional photograph). The features that are labeled would be more than adequate for discussion in the text, as they include wonderful examples of many aspects of lunar geology. All of this having been said, I still find this book to be very useful for planning observing sessions, since it makes it easier to determines which areas of the Moon are most likely to be fruitful for observation. As a planning tool Moon Observer’s Guide can help the observer more effectively use a larger (and more expensive) full scale atlas.

The final third of the book covers three topics. First is a discussion of what to do with your observations, and this covers everything from taking notes, sketching, and the use of various imaging technologies to record the Moon. As is the case with all the other subjects taken on by the author, these are dealt with briefly, in a way that to my mind is meant to get the reader started, providing suggestions and possibilities. It is not a definitive guide to lunar imaging, and given the apparent aim of this book to be an introduction to matters lunar, this would have been an inappropriate approach to the subject. This is not, after all, a book about using CCDs to image the Moon. (That having been said, the suggested reading material listed near the end of the book could have done a better job of pointing the reader toward more information on imaging.) The section on sketching was enough to move me a large step closer to being any good at this style of illustrating lunar observations. The author provides one of the best rationales for observing with a pencil and a sketch pad I’ve ever read. The book moves on to an explanation of how and why eclipses, lunar and solar, come to happen. Only the techniques for the observation of lunar eclipses are covered in any detail, but the book is no poorer for neglecting the solar counterpart (about which entire books have been written in any case). And last, but of course not least, is an overview of the exploration of the Moon by robotic probes and the Apollo missions.

I am a bit puzzled by the way subject matter was divided and wrapped around the map-oriented portion of the book. The material on how to observe, for example, would have directly complimented the material on the gear to use while observing. And the explanation of eclipses fits right in with the other

file:///Users/asaint/cloudy/books/moon.htm (4 of 5)8/16/2004 8:33:52 AM Cloudy Nights Moon Observers Guide Copyright (C) 2004 Cloudy Nights Telescope Reviews matters in chapter two (“The Moon in Space”). However, the oddity of chapter arrangement does not seriously weaken the book, much less reduce its usefulness. Different strokes for different editors.

Just so no one is confused by the small number of flaws I’ve pointed out in this brief review, I was quite pleased overall by the Moon Observer’s Guide. Taken as a whole, Peter Grego’s book is a good quick reference and planning guide that I have already put to considerable use. For the new lunar observer this book would be hard to beat for an introduction to the basic concepts of Moon watching. It is very easy to overwhelm a new astronomy enthusiast with a welter of labeled detail, and the Moon certainly has more than its fare share of named features. The maps in Moon Observer’s Guide provide (and label) just enough detail to enable the beginner to become oriented with minimal confusion. Larger atlases, which exist for the purpose of covering that wealth of detail, can also be overwhelming in terms of price, another problem Moon Observer’s Guide avoids. I highly recommend Peter Grego’s Moon Observer’s Guide to all Lunartics. For experienced observers it can be a handy tool. For beginners, it’s an affordable, accessible introduction to the wonders of the Moon.

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