Hypothetically, let’s say you’re an avid, visual, deep-sky observer. Let’s also say that you own a decent size telescope, say maybe a 13.1” Dobsonian, and you’ve already observed all of the Messiers, the Caldwells, and the brighter NGC’s. Now you’re after the more obscure variety of fainter and fuzzier faint fuzzies, perhaps you’re working on the Herschel 400 list. Nothing satisfies you more than tracking down and identifying 12th magnitude (and fainter) galaxies in a sparsely populated region of the sky with few guide stars. (Sound like anyone you know? Nah!) Well, if this describes you, then you might not know it yet but you need a copy of Uranometria 2000. Let me explain why.
First of all, what is Uranometria 2000? Uranometria 2000 is a two volume star atlas, co-authored by Wil Tirion, Barry Rappaport, and George Lovi, first published in 1987 by Willmann-Bell, Inc. It consists of 473 separate charts, with more than 300,000 stars plotted down to magnitude 9.5, plus more than 10,000 deep-sky objects. The first volume covers the northern hemisphere from the north pole to -6 degrees declination, while volume two covers the southern hemisphere from the south pole to +6 degrees declination (thus providing 12 degrees of overlap between the two volumes). What makes this atlas most notable is the scale of the charts. Each one covers 11 degrees of declination and around 32 minutes (more near the poles) of right ascension. For example, at this scale the Andromeda Galaxy, Messier 31, appears as an oval more than two inches long! These charts are detailed baby!
Now if you’ve been observing for a while, you are probably using the ubiquitous Sky Atlas 2000, which is the staple of many a visual observer. By comparison, its 26 charts contain some 43,000 stars down to magnitude 8, and about 2500 deep-sky objects. On its chart, M31 barely extends three quarters of an inch. Now don’t get me wrong - Sky Atlas 2000 is a fine atlas. I’ve used mine for more than fifteen years and I still use it most of the time. It is ideal for tracking down all the Messiers, the Caldwells, and most of the brighter NGC and IC objects. But for the owner of today’s larger telescopes, it has its limitations. Many objects that are within the grasp of a 12-inch or larger scope are not plotted, or there aren’t enough field stars plotted to allow star-hopping to find them. Also, the scale of the charts sometimes can make positive identification of that fuzzy patch difficult if not impossible.
With Uranometria 2000, both shortcomings are resolved. With nearly ten times more stars, and about four times as many deep-sky objects plotted, much more of what you can see in your eyepiece will be plotted on the chart. With the scale of the charts and the extra magnitude and a half of stars that are plotted, positive identification becomes much more achievable. More often than not, brighter field stars that are visible through the eyepiece are plotted on the chart, letting you get a positive match between the two. Once you do that, you can be confident that you are actually seeing what you think you’re seeing.
Case in point. On the night of August 20-21, Mark Deprest, John Causland, and a couple of others and I were out at Peach Mountain on a remarkably clear night. The sky was about as transparent as it gets at The Hill, especially in August. Mark was looking at doubles, John was using his 18 inch “suitcase scope”, and I was working on my usual fare - obscure, faint, and unimpressive galaxies, with my 13” dob. Mark mentioned something about some galaxies in Delphinus, the Dolphin, that we ought to track down. I opened up chart 16 in Sky Atlas 2000, but there wasn’t a galaxy to be found in Delphinus. But, in Uranometria 2000, there are at least a dozen! Using its detailed charts, we were able to star-hop to a few of them, some with surface brightnesses below 13 magnitudes per square arcminute. The galaxies we saw, NGCs 6927, 6928, 6930, and 6944, simply would not have been possible using Sky Atlas 2000.
Uranometria 2000 also has some other uses. Often times, after I’ve bagged one of my Herschel list objects, I’ll notice some nearby objects on the chart that I wasn’t originally looking for. I’ll then take time out and look to see which of those other objects I can track down. Or, you can simply pick a chart and go for it. One night at the Texas Star Party in 1998 I started on and never left charts 193 and 194, in the heart of the Coma Berenices/Virgo galaxy cluster. I observed and logged more than fifty new galaxies (not including the usual Messiers) that night. It was galaxy-hopping at its finest!
A companion to Uranometria 2000 is the Deep Sky Field Guide to Uranometria 2000. This highly useful guide provides tabular data for virtually all the deep-sky objects found on the charts. The data is tabulated by chart number, and organized by object class (open cluster, planetary nebula, galaxy, etc.). While not purely essential for observing, it provides a wealth of information on virtually anything you want to observe.
So do you really need Uranometria 2000? Maybe not. For one thing, it’s a little pricey - about $80.00 for both volumes plus another $50.00 for the field guide. But if you’re a visual observer with a moderately large scope, then it will help you discover that there is much more “out there” within the grasp of your eyes and telescope than you ever realized. I can tell you that it did for me. If you own a really big scope, say an 18-inch or larger, I would say that it is essential.
Now the question is, do I need Millennium Star Atlas? Hmmm...