Great Atlas of the Sky - a personal observation (Part 1 of 2)

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by , 04-25-2016 at 04:59 AM (3306 Views)
Hi, my name is Alan and I am an atlaholic. With that candid confession, I will say I have never met a printed sky atlas that I didn’t like, though I do like some more than others. Since I do not use electronics at the scope I have developed a real love of printed atlases and charts over the decades. Of course at one time that was all we had anyway so that love was born of necessity a long time ago, but has continued even with the popularity of electronic atlases and charts.

Recently I had the opportunity to purchase a barely used copy of the Great Atlas of the Sky (GAS), which was released a few years ago to commemorate the 400th anniversary of the telescope. Though it is no longer being produced it is sometimes available in the used market. When it was in production, it was marketed as largest atlas in print. I have now had the chance to give it a good look and wanted to share my thoughts about it with everyone.

A point that should be made is that this atlas is quite large and heavy weighing in around 12 lbs. It is therefore not really a field atlas at all, rather an excellent desk reference. First let’s take a look at what this atlas offers the observer.

Stars: Contains over 2.4 million stars plotted through magnitude 12.0; of which over 130,000 are labeled with Bayer designations, Flamsteed numbers or numbers from the Hipparcos catalogue. There are also almost 25,000 variables from the General Catalogue of Variable Stars and almost 80,000 double/multiple stars from the Washington Double Star Catalogue.

DSOs: Over 70,000 galaxies, clusters, and nebulae from the following references: Messier, New General Catalogue, Index Catalogue, Principle Galaxies Catalogue (PGC), Sharpless Sh-2 Catalog of H-II Regions, and the RCW Catalogue of H-alpha emission regions in the Southern Milky Way. Galaxies larger than 2 arc minutes, and clusters and nebulae larger than 5 arc minutes are plotted showing their shape, size and orientation. Smaller DSOs are shown more generically.

Charts: Nearly 150 bi-fold pages printed on both sides, yielding 296 charts with dimensions of 24x17 inches when unfolded. The charts appear to be printed on glossy magazine type paper of a little heavier stock than a magazine, though they can certainly be easily torn, especially at the binder holes. There is also an index page showing the layout to aid in finding the proper chart that is printed on heavier stock. Stars and DSOs are plotted using black and/or gray on a white sky. The scale of the atlas is a large and roomy 37mm per degree, thus allowing the plotting of such a large number of stars and objects without being saturated. Each chart has a key along the bottom of the page displaying star and object size graduation scales as well as indicators of what chart numbers adjoin the one being viewed to the top/bottom and left/right.

It also comes with a large acetate overlay with several smaller graduated Ra/Dec grids to aid in plotting. The package also includes a large stiff clear plastic sleeve into which one can slip a folded chart to protect it in the field.

Binder: The entire atlas is contained within a nice quality leatherette four-ring binder with gold embossed lettering on the front cover. The binder is approximately 14 inches wide, 19 inches tall and 2 inches thick when closed, and has a zippered closure to keep the contents safe and sound. The index page and charts are punched for the rings while the overlay resides in a pocket inside the front cover. Already knowing that the charts have the potential to tear at the binder holes, I purchased more than enough clear reinforcement rings to protect all the bound pages on both sides (almost 1200 rings). That was a laborious project in and of itself but I felt that given my investment it was well worth the time expended as eventually I would have to repair torn holes anyway. Therefore I decided to be proactive and put them in place before needed.

Initial impressions: This atlas is truly a work of art, and from its highly detailed charts to the beautiful leatherette binder, it is built to impress. However, it is not an atlas that I would recommend to beginning or casual observers given its size, weight, depth and cost. My wife even commented to me more than once about the beautiful appearance of the atlas.

A few things I like: I think the main thing that really stood out for me is its sheer impressive stature, both in detail and build.

From a more detailed perspective, as a galaxy hunter I am astounded by the volume of star islands plotted. One specific area I checked as a comparison between the GAS and my primary field atlas, the Interstellarum Deep Sky Atlas (IDSA), was the background galaxies to be found in the field of the famous open cluster Messier 44 in Cancer. The IDSA plots only the two brightest galaxies visible between the stars of the cluster, while the GAS plots eight. That is not surprising given the design differences between the two. I also specifically looked at a pair of Abell galaxy clusters in Hercules, 2197 and 2199. The IDSA plots a handful of member galaxies in each cluster. The GAS on the other hand plots a multitude of galaxies associated with these two clusters from the PGC catalogue, as one would expect

A few things I don’t like as much:
First let me state that no one atlas does everything perfectly, and the GAS is no exception to that rule. That is one of the advantages of having several atlases, as I can have most, if not all, of the bases covered. What one may not plot, another may. This atlas doesn’t have any shortcomings that are of significant importance to me personally, with most falling under the broader category of minor nit-picking, which can be done with any atlas

I think the main obvious deficiency of this atlas is that it does not appear to plot any dark nebulae. While that is not a show-stopper for me personally, it might be for the next person. It was interesting to not find the immense Pipe Nebula complex in Ophiuchus plotted in this atlas, nor any other dark nebulae I specifically looked for, as even the Pocket Sky Atlas displays the Pipe Nebula.

Other things I ran across in a short comparison is that the GAS does not plot the Palomar globular clusters except for Palomar 7 which also carries the designation of IC 1276 and Palomar 9 also known as NGC 6717. These two are plotted only by their respective designations in the IC and NGC catalogs with no mention of their Palomar label. The IDSA plots all the Palomar globulars, though in the case of the aforementioned two objects it also shows only their respective IC and NGC labels. The IDSA also plots the more elusive Terzan globulars as well as other even more challenging globulars.

I mentioned the Abell galaxy clusters AGC 2197 and 2199 above as areas where the GAS plotted many more galaxies than does the IDSA, which I liked. However, on the flip side of that positive I did note that the GAS does not label the galaxy clusters as a distinct entity, only the individual member galaxies. Again this falls under the category of a very minor complaint. In that same vein I also noted that it does not label other groups such as the Hickson compact galaxy groups, though it may plot most of the members in many of the groups. Again not a major drawback, but something I would have preferred. Of course these things are all at the discretion of those that designed the atlas.

I will also toss out one more minor issue I have with the GAS (as well as Uranometria), that being the fact that it does not have the stick figure lines drawn in for constellations. Personally I find them useful for gaining perspective when looking at an atlas. Yet again, another non-critical nit, but something I like to see in an atlas.

(Concluded in Part 2)
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