One of my favorite objects to observe are Globular Clusters. This time of year, they are beginning to reign supreme as our own galactic plane rides higher and higher between Scorpius and Sagittarius. These fuzzy balls of light, as many a back yard stargazer describes them, vary in their central concentration of stars. They are officially organized in classes, ranging from Class I (very high central concentration) to Class XII (almost no central concentration). Here is a quick tour of some of the most prevalent visible this time of year, and should be on your observing list the next time your out for sure.
M 53 - Coma Berenice, Mag= 7.7, R.A. = 13h 13.54m, Dec = 18° 05.9'
We start off our tour on the most western globular cluster, located in Coma Berenice. I was surprised by how bright this cluster was in the eyepiece (Most observing is with a C8 btw). There was a nice star field, and I could certainly resolve stars on the outer fringes of the cluster, but did not pick up any central concentration on this night myself, nor was I able to resolve stars across the core directly. Still, lurking around the edges was fun, and averted vision really helps pick up the finer details hiding in this wonderful globular cluster. M53 is classified as a Class V.
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| Digital sketch I did at the eyepiece, using SketchPad Mobile for iPod. |
M 3 - Canes Venatici, Mag= 6.3, R.A.= 13h 42.80m, Dec = 28° 19.1'
What a great globular cluster this is, with nice detail visible on the outer edges of the cluster, and hints of stars speckled across the core. Averted vision really allows you to pick up the central stars, but the core appeared almost uniform in brightness to me, with no real central brightening that I could pick up visually at the eyepiece. Simply splendid. M3 is listed as a Class IV.
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| Live view snapshot with C8 @f6.3 & Samsung SCB2000 camera |
This is one of my favorite globular clusters! Now personally, whenever I view M5, it appears to me like a stunning spiral galaxy, with swirls of stars emulating out from a nice, bright core. Of course that is just an impression, since the stars that make up this glorious globular cluster are fairly easy to pick up on the outer fringes, and indeed I can just pick up individual stars across the core, which I can also pick up a nice brightening. M5 is Class V.
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| Meade LS8 ACF, DSI II Camera |
M 13 - Hercules, Mag= 5.8, R.A = 16h 42.17m, Dec = 36° 25.6'
Now you can't talk about globulars with talking about the Great Hercules Cluster, M13. This monster is noticeable even in my 6x30 finder, and is always a winner at the eyepiece. No issue at all, unless you have bad transparency, in resolving stars clear across the core. You can even get more detail when you up the power on this beauty, but for me the most enjoyable view is always medium to low power. M13 is a Class V.
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| Live view snapshot with C8 @f6.3 & Samsung SCB2000 camera |
This globular cluster resides in Hercules, so M13 obviously steals a lot of the thunder from what is actually a very bright cluster itself. I was surprised at how bright M92s core appeared to me, in fact, I guess its safe to say that its mostly core in the eyepiece, with a scattering of stars thrown about its central concentration. No way near the spectacle of stars that M13 presents, it still offers a very pleasing view. I can also easily pick up this small, bright ball of light in my 6x30 finderscope, and when in the field of view at medium power, you too should be impressed by how well M92 puts on a show against its larger brethren in Hercules. M92 is a Class IV.
M 10 - Ophiuchus, Mag= 6.6, R.A. = 16h 57.79m, Dec = -4° 08.2'
This is the best globular in Ophiuchus, nicely defined circular ball of light that I can easily pick up its outer stars. Now for its core, I pick up only a slight brightening, and with averted vision, just a few stars at best across the central concentration. M10 is a Class VII.
M 12 - Ophiuchus, Mag= 6.1, R.A.= 16h 47.88m, Dec = -1° 58.4'
M12 is dimmer then M10, but I can still pick up stars on the outer two thirds of this cluster. I did not however discern any centralized brightening of this Class IX globular cluster.
M 14 - Ophiuchus, Mag= 7.6, R.A.= 17h 38.29m, Dec = -3° 15.4'
This globular was dim, with no real ability to pick up stars until the very, very edges. A typical "fuzzy ball" as my field notes documented. M14 is a Class VIII.
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| Live view snapshot with C8 @f6.3 & Samsung SCB2000 camera |
M 80 - Scorpius, Mag= 7.3, R.A = 16h 17.88m, Dec = -23° 00.9'
This is a very bright globular cluster, and very easy to see a bright core visually. I can also pick up some individual stars of this beautiful ball of light on its outer edges, but nothing resolvable across the core itself. M80 is a Class II.
This globular proves a challenging object to pick up visually for me. It could be my local conditions, and the fact that where Scorpius is located in my sky is closest to downtown, and thus more heavily light polluted, but it can also be the fact that its just not a dense core cluster like the neighboring M80. In my 12" Apertura dobsonian, I can start to resolve this globular, but in my 8" scopes, I need nights of very good transparency and with averted vision I can begin to see the stars themselves across this ball of light. M4 is a Class IX.
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| Live view snapshot with C8 @f6.3 & Samsung SCB2000 camera |
M 22 - Sagittarius, Mag= 5.2, R.A.= 18h 37.10m, Dec = -23° 54.3'
Magical is how I describe M22. This is a stunning globular cluster, in fact the very first time I viewed it I thought I was viewing a very dense open cluster! Wait to view this globular until Sagittarius is the highest it will be in your sky, and you will be treated to an eyepiece full of stars, like someone poured sugar on a black velvet blanket. Most of the time I don't even need averted vision to pick up the stars all they way across this glorious object, but it certainly helps. Now the cluster appears very uniform to me in brightness, with more or less the central core simply a denser region of stars, thus making it appear a tad brighter. M22 is a Class VII.
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| Live view snapshot with C8 @f6.3 & Samsung SCB2000 camera |
We wrap up this tour of globulars with M28, a rather average cluster itself, but still visually appealing. I can begin to resolve stars on its outer edges with averted vision in my 8", with my 12" considerably improving the view, and hinting a stars across its core, which has a slight brighten. M28 is a Class IV.
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| Live view snapshot with C8 @f6.3 & Samsung SCB2000 camera |
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