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Sky & Telescope's Pocket Sky Atlas


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Sky & Telescope's Pocket Sky Atlas
by Michael Coren




Introduction: My Life Story

I've been interested in astronomy since a school trip to the planetarium when I was 6 or 7 years old. I'd like to say it was the beauty of the night sky and the harmony of its movements that captivated me, but more likely it was a way for me to "connect" with Captain Kirk and Will Robinson. Whatever the motivation, I got my first telescope when I was 10 or 11 years old, a 3-inch f/10 reflector from Edmund Scientific. When I was in high school in the early 1980's, I bought my first "serious" telescope, a used 8-inch Dynamax SCT, through an ad in Sky & Telescope magazine. After keeping that scope for far too long (20+ years), I replaced it with a Celestron 9.25-inch SCT on the Advanced Series CG-5 GOTO mount. I never really used the GOTO capability all that much since I find starhopping to be much more fun, so I sold that scope and ordered a 12.5-inch Discovery dob. Until that arrives, my main scope is a 6-inch Meade LXD75 Schmidt-Newtonian OTA on an Orion SkyView Pro mount.

What I Was Looking For In An Atlas

I live in the heart of the Washington DC suburbs, just outside of the Capital Beltway in Virginia. The amount of sky I can see from my back yard is limited by surrounding trees, but fortunately none of my neighbors keep their outside lights on in the back so it is reasonably dark at ground level. On nights of exceptional seeing, I may be able to make out stars down to magnitude 3.5 or 4 with my unaided eyes.

As a member of NOVAC, the Northern Virginia Astronomy Club (www.novac.com), I am privileged to have access to some reasonably dark observing sites, but even the nearest of these is a good hour drive from my home. When I make the trip, I bring along my laminated field edition of Sky Atlas 2000. For quick observing sessions from home, however, its large size (18-1/2 x 14 inches) and weight (nearly 5 lbs) make it awkward to carry out with my hands full of other gear.

For some time, therefore, I have been on the lookout for a good "grab-and-go" star atlas that I could use for quick observing sessions from home. I tried Orion's DeepMap 600 but found that it didn't have nearly enough detail for actually finding the objects it showed. I also tried the otherwise excellent Cambridge Star Atlas, but I didn't like its hardbound format, and I felt the scale of the charts was a little too small for starhopping with a 9x50 finder scope.

It was with much interest therefore that I noted the announcements of the new Sky & Telescope's Pocket Sky Atlas earlier this year. Once they were actually in stock and shipping, I went ahead and ordered one. The atlas is available through Sky & Telescope's "Shop at Sky" web site (www.shopatsky.com) for $19.95 plus shipping. It is also available through other online retailers, often at a significant discount, and I'm sure it can be purchased or ordered through traditional "brick and mortar" bookstores as well.

Structure Of The Atlas

The atlas is 6-1/2 x 9 inches, not exactly "pocket" size but certainly small enough to fit easily into a backpack, equipment case, or glove compartment. The atlas is wire bound so it will lay flat when open or can be easily folded back on itself, a big advantage over the hardbound book style of atlas. The atlas is printed on thick, heavy paper, with a smooth but glare-free finish. I do not believe the pages are water proofed, so I don't know how well they will hold up to repeated exposures to dew.

A brief but well-written introduction by Roger W. Sinnott explains the layout of the atlas and the information it contains. The main atlas comprises 80 charts, organized as 8 groups of 10 charts, each group of 10 charts covering approximately 3 hours of right ascension from the north celestial pole to the south celestial pole. The numbering of the charts is regular and consistent such that charts numbers ending in a "1" are at the north celestial pole, charts ending in a "4" or "5" are the celestial equator and regions immediately north, charts ending in "6" or "7" are the celestial equator and regions immediately south, and charts ending in "0" are at the south celestial pole. There are generous amounts of overlap in coverage between charts (as much as 10 degrees or more in some cases), which makes it easier to starhop across individual chart boundaries. As explained in the introduction, the actual region plotted on each chart was shifted in some cases so that well-known asterisms such as the Big Dipper or the Great Square of Pegasus could be contained within a single chart.

A chart key is conveniently included on the inside of the back cover, and this positioning makes it very easy to find (I always have to hunt for the chart key in Sky Atlas 2000). The key is also reproduced at the beginning of every one of the groups of 10 charts, indicating which group you are up to. The inside of the front cover contains a diagram explaining the layout of each chart page, a ruler showing the scale of the charts (approximately 5 degrees per 24 mm), and an illustration of a Telrad reticle printed to the scale of the atlas.


Chart Key on inside of back cover

The main charts plot stars to magnitude 7.6, galaxies to magnitude 11.5, globular clusters to magnitude 10.5, and planetary nebulae to magnitude 12. All 400 objects in the Herschel observing list are shown, even though some would not meet these criteria. All 109 Messier objects are identified in the charts by their M numbers, but not their NGC numbers. Caldwell objects, on the other hand, are identified in the charts by their NGC numbers, but not their Caldwell numbers. For both the Messier and the Caldwell objects, there are appendices in the back which cross-reference the Messier or Caldwell numbers with their corresponding NGC numbers and the chart(s) where they can be found.

The charts show "stick figure" constellation shapes with green lines. I consider this a welcome enhancement over Sky Atlas 2000, since it provides some additional context for where the particular chart "fits" into the larger shapes you see in the sky.

A legend is included at the beginning of each group of 10 charts, but not on every page like in Sky Atlas 2000. I think this is fine as the symbols and colors are consistent with other atlases. About the only information that I think might have been helpful to reproduce on each page is the stellar magnitude legend.


Chart Legend on first page of each group of 10

Following the main charts, there are four "Close-up Charts" showing greater detail in the Pleiades (showing start to mag 12), Orion's sword (to mag 11), the Virgo cluster (stars to mag 9), and the Large Magellanic Cloud (stars to mag 10).

All in all, this atlas packs an impressive amount of information in a convenient package.

Using The Atlas

As impressive as it looks indoors, the true test of an atlas is how usable it is to actually find things out in the dark. I took it for a test drive one clear April evening in my back yard with my 6-inch Schmidt-Newtonian and 9x50 finder scope on a SkyView Pro equatorial mount.

The area around the Virgo cluster was high up and visible through the opening in the trees when I set up, so I decided to go through some of the galaxies there. Even though there is a close-up chart showing the Virgo cluster in greater detail in the back of the atlas, I chose to use chart 45 in the main section of the atlas since I was interested in getting a feel for the usability of the overall atlas. I also decided to stick mostly (but not exclusively) to Messier objects, since I am working on my Messier certificate and because these are more realistic targets from the light-polluted suburbs than other, more obscure NGC objects.

After centering Denebola in my field of view and making sure my finder scope was aligned, I jogged a bit north and shot east to where the atlas indicated M98 should be, but I couldn't see it. I was able to hop over to M99 nearby so I knew I was in the right place, so I'll chalk it up to my light polluted skies. From there I continued up to M100, and then up to M85 and I think I could see NGC 4394 in the field. So far, so good.

M64 was my next stop, and I found it easily but could not make out its "black eye". From there I hopped over to NGC 4565, being pleasantly surprised to come across NGC 4494 along the way. Then it was back down to M85 and from there a quick dash over to the globular cluster NGC 4147.

By this time Arcturus was coming up over the house, so I swung over to Muphrid (Eta Boo) and hopped up from there to globular cluster M3 in Canes Venatici. I found that with an 8mm Radian in my SN6 giving 95x, I could start to resolve the outer fringes of M3. From there I flipped the page over to chart 43 and ended the evening by hopping up to M63, the "Sunflower Galaxy."

All in all, I was quite pleased with this little atlas, having found it easy to correlate what was shown in the atlas to what I could see in my finder scope as I moved between objects. I did see a number of fainter stars in my finder scope that weren't plotted in the atlas, but not so many that it was confusing or difficult to relate the view to the atlas. Under darker skies, however, this might be a problem, but again, my need was for a "grab and go" atlas to use in my suburban back yard.

In the main atlas page containing the Virgo cluster (chart 45), only Messier objects are labeled in the densest region of the cluster between Denebola and epsilon Vir. The other objects in this region are shown on chart 45, but not labeled. This is understandable given the density of galaxies in this region, and the fact that there is a close-up chart of the Virgo Cluster in the back of the atlas that labels all of these objects. For reasons previously stated, I chose not to use the more detailed chart, so I can hardly consider this a complaint about the atlas itself.

Back inside later that evening, I noticed a printing error in the Virgo Cluster close-up chart in the back of the atlas. Specifically, on that close-up chart, it looks like something prevented the black ink from printing in a small area around where rho Vir should be. There are two red circles that presumably indicate the positions of NGC 4596 and 4608, but no black text or symbols in the immediate area. The grid lines are broken, and neither rho Vir nor nearby 6th magnitude 27 Vir are present.

Using with GOTO

So far, I have focused on the usability of this atlas for starhopping, since that is how I enjoy observing and my main application for this atlas. On the other hand, I can certainly see this atlas finding a home in many GOTO-users' observing kits, particularly those with larger aperture scopes or who have access to rural dark skies. Such users may find this atlas very helpful in identifying some of the more challenging objects that are within their reach, or in seeing what other treasures may be close to a particular observing target. Users of small or medium sized GOTO scopes may find something like Cambridge or Orion's DeepMap 600 more suited to getting an idea of what is visible.

Conclusion

This atlas is a definite winner! It fills a conspicuous need between the mag 6 "binocular" atlases such as Cambridge, Norton's, and Bright Star, and the larger, and more detailed atlases such as Sky Atlas 2000, Uranometria, and Millenium. Sinnott and the team at S&T who designed it are obviously experienced observers who know what information is useful to the observer and took the time to organize it well. While it may not have the depth needed for large apertures under dark rural skies, it does what it does very well. It certainly meets my need for a "grab and go" atlas for finding objects under light-polluted suburban skies.

Summary

Sky & Telescope's Pocket Sky Atlas by Roger W. Sinnott
© 2006 Sky Publishing Corporation, Cambridge, Mass, USA.
ISBN 1-931559-31-7

Pros:
  • Small and light, easy to hold with one hand while observing.
  • Printed on thick heavy stock with smooth, glare-free finish.
  • Generous amounts of overlap between adjacent charts.
  • Easy to lay flat or fold back on itself.
  • Charts are well thought out and well laid out.
  • Green stick figures of constellations provide additional context for individual charts.
  • Chart key is easy to find on inside of back cover.
  • Commonly used information (chart key and legend) is repeated at regular intervals.
  • Close up charts show further detail in areas of particular interest to amateurs.
  • Excellent for starhopping in light polluted skies


Cons:
  • Not sure of durability after repeated exposure to dew
  • May not have enough detail for effective starhopping under dark rural skies
  • The S&T subscription card bound into the back is tacky!


  • RobertED, slpavela and condor777 like this


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