Notes from Under Sky

The Messier Objects

In which I review this book

Title: The Messier Objects, by Stephen James O'Meara
Price: about $35
Published 1998 by Cambridge University Press and Sky Publishing Corporation
ISBN 0-933-34685-9, 318 pp.

A year or two ago, Tele Vue began running a series of magazine ads in Sky and Telescope (and possibly in Astronomy as well) which featured Stephen O'Meara's sketches of various deep-sky objects as seen through his 4-inch TV Genesis. His sketches showed an astonishing amount of detail for any kind of scope, let alone a smallish refractor.

O'Meara, a contributing editor at Sky and Telescope, may have been made those sketches as part of the work for his book, The Messier Objects, one of the Deep-Sky Companions series that is a joint offering of Sky Publishing and Cambridge University Press. Here, they accompany photos and descriptions of each of the 109 objects Charles Messier recorded in order to avoid mistaking them for comets, his true quarry.

The Messier Objects is a very nicely produced book. It's divided into six chapters and four appendices, covering such diverse topics as the history of the Messier objects, some general tips on how to observe them, non-Messier objects that perhaps should have been, and so forth.

The heart of the book, however, is Chapter 4, which consists of a nearly consecutive listing of the Messier objects. (Nearly, because M84 and M86 are treated together; there are other pairs, but those are all next to each other.) Each entry includes a photo, a finder chart, the object's location and other vital statistics, and of course, one of those splendidly detailed sketches.

The finder charts are not as easy to use nor as complete as those in another book devoted to the Messier objects, Harvard Pennington's The Year-Round Messier Marathon. Perhaps Pennington's initial difficulties in finding objects led him to place extra emphasis on helping the novice learn hunting skills. On the other hand, O'Meara offers us much more description and history behind the objects than Pennington does, and his organization lends itself much easier to armchair reading. In a way, these two books complement each other rather well.

The Messier Objects could use a bit of editing polish; there are small and easily remedied errors throughout the book. For example, on p. 28, O'Meara gives Tim Hunter's dark site rating formula:

OSI = (T+W+A+S+V)/C

where OSI is the observing site index, T is the transparency expressed as the limiting magnitude, W is the weather expressed as percentage of clear nights per year, A is altitude in thousands of feet, S is the seeing on a scale of 1 to 10 (10 being best), V is the visibility in terms of the percentage of unobstructed sky, and C is convenience, with 0 being worst and 1 being best (at least according to O'Meara).

Right off, you can see there are problems, because a low convenience will increase the rating rather than decrease it. Furthermore, O'Meara rates his own site as follows:

OSI = (8.0+0.75+4000+8+0.9)/90 = 45

When I first saw this expression, it struck me as rather odd that altitude was so dominating, until I recognized that O'Meara's expression gave his altitude as 4 million feet. That works out to 800 miles or so, which would give you outstanding transparency if the hypoxia didn't hit you so rapidly. Also the convenience, which is supposed to be a number between 0 and 1, is instead given as 90. I can't divine what that's supposed to mean. Clearly, something is amiss here, and it would seem to be a simple matter to fix.

Another item worth mentioning is O'Meara's implicit contention that M102 is merely a duplicate observation of M101. In this, he is in agreement with Pennington, but whereas Pennington at least mentions the school of thought that proposes NGC 5866 (the Spindle Galaxy), O'Meara apparently regards the matter as closed. It's a little as if a Stratfordian had never heard of Edward de Vere. Hopefully, it's just an oversight. See

for additional details on this topic.

The outstanding feature of this book is, of course, O'Meara's sketches. A previous reviewer in Sky and Telescope (which you might hesitate to regard as unbiased, since they sell the book, too) indicated that he thought at first that they were made with an 8 or 10-inch scope, rather than the 4-inch Genesis that O'Meara actually used. Even with the photos, the sketches provide another view, one that is hopefully closer to what one might see through the eyepiece, given a good amount of patience.

Indeed, the sketches are incredibly—almost too—detailed. The pictures of nebulae show fancy spans of gas arcing between bright stars; these are barely visible even in many photos and are a silent testament to O'Meara's observing and sketching skill. He goes too far, however, in extending the same treatment to open clusters which are not noted to have any nebulosity. At times it seems as if a child has gone stone cold nuts dot-to-dotting the stars. The patterns may be there, but they are in the mind's eye, and as with all such patterns, different observers come up with different results; it's counterproductive in my opinion to thus prejudice new observers.

Many beginning observers will buy this book as a guide in observing the Messier objects for the first time, and the sketches will certainly serve the pedagogical purpose of pushing them to see all that they can see. (Not to discourage novices too much with his observing skill, O'Meara points out the difficulty he had in finding M74 even with a 9-inch refractor!) It's beautifully produced, and makes a handsome addition to any astronomy library. Even with a few peculiar errors and those oddly decorated sketches of open clusters, I can recommend it.

Copyright (c) 2000 Brian Tung