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Question about NGC 2158

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#1 Special Ed

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Posted 23 January 2013 - 09:55 PM

Hello,

I was looking at some OC's the other night with my 35cm Cat and after observing M35 for a while (beautiful curving strings of stars) moved over to NGC 2158. I looked at 98x and 170x but the cluster never looked like more than a hazy patch.

Conditions were not the best--3/10 Pickering seeing and a 1st quarter moon. Transparency was ok in the vicinity of the OC. I wouldn't have even been observing DSO's with those conditions but the weather has been so cloudy here I hate to waste any clear skies.

I'm wondering if stars can be resolved in this distant cluster if enough magnification is used and conditions are better than they were for me that night. I am assuming they can, especially with my aperture, but I don't have much experience looking at DSO's with my big Cat.

Anyone have any thoughts on this?




#2 sgottlieb

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Posted 23 January 2013 - 11:26 PM

Your C8 should do the trick, actually. But as always in regards to resolving clusters, both the darkness of your skies and use of high power (and good seeing) are important factors. Here are my notes through a variety of apertures ---

18" (2/24/06): at 323x, this rich, irregularly shaped cluster is beautifully resolved into 45-50 stars that are peppered over a 5' background glow. Appears like a resolved globular of low concentration class. Includes a couple of dozen mag 13.5-14.5 stars along with a rich carpet of fainter mag 15 stars. There are several close pairs (1"-2" and possibly closer) and the number of stars keep increasing in moments of rock steady seeing as they seem to emerge from the background. A single brighter star is at the east edge.

17.5" (2/8/86): 30-35 stars resolved, unusually rich, compact, about 5' diameter. The appearance is similar to a resolved globular cluster. Located 30' SW of M35.

13.1" (2/16/85): at least 20-25 stars resolved at 415x.

13.1" (11/5/83): ~15-20 stars, mottled clump near SE edge.

8": few stars resolved over haze.

80mm (1/20/07): visible in the finder at 13x as a very faint, small glow about a half-degree SW of M35.

#3 David Knisely

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Posted 23 January 2013 - 11:47 PM

In my 8 inch f/7 Newtonian, I can see around 20 to maybe occasionally close to 30 faint stars in NGC 2158, but it does require very good seeing and dark sky conditions plus some moderate to high power to do it. I like using from 120x to 220x on the cluster, as at lower powers, it just looks like a hazy somewhat granular glow. Clear skies to you.

#4 Special Ed

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Posted 24 January 2013 - 08:24 AM

Steve and David,

Thank you very much for your responses--much appreciated. You might be interested in seeing this excellent sketch of M35 and NGC 2158 by Peter Vercauteren which prompted my question. It was done with his 18" dob @ 85x.

#5 Achernar

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Posted 24 January 2013 - 09:35 AM

You'll need a large telescope and a dark sky to do it, but it is possible. NGC-2158 is actually larger and far more luminous than M-35. But it's immense distance of 16,000 light years and the absorption by interstellar dust dims it so much, only large telescopes, those in the 16-inch class and above reliably show the brightest stars in any number, which are at 15th or 16th magnitude. If you see it in a smaller telescope, you have very good eyesight and sky conditions, a 12-inch might do it too. I have wanted to see if I could resolve it myself with the 15-inch I built, but local sky conditions never were very good whenever I had the idea to try it.

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#6 nytecam

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Posted 24 January 2013 - 12:11 PM

This is a fine OC - my pic from Nov 2011 via my M12 :grin:

#7 Special Ed

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Posted 24 January 2013 - 04:50 PM

You'll need a large telescope and a dark sky to do it, but it is possible...
Taras


Thanks for the input, Taras. I have a fairly large telescope and very dark skies so I am hopeful-- clear skies are another matter. If you can get yourself and your 15" scope to some dark skies while Gemini is so high, I'd be interested in reading your report. :)

Maurice-great image. What a bunch of colorful stars! :cool:

#8 Achernar

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Posted 24 January 2013 - 05:11 PM

Maybe in a month or two that will materialize, before Gemini is in a poor position for observation. Given the milky and heavily light polluted skies along the Gulf Coast, I expect NGC-2158 to be a patch of light wtih stars flickering into and out of view, in other words it will probably hint at resolved stars, but that is probably the most I could hope for.

Taras

#9 Starman81

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Posted 25 January 2013 - 01:00 AM

Your C8 should do the trick, actually. But as always in regards to resolving clusters, both the darkness of your skies and use of high power (and good seeing) are important factors. Here are my notes through a variety of apertures ---

18" (2/24/06): at 323x, this rich, irregularly shaped cluster is beautifully resolved into 45-50 stars that are peppered over a 5' background glow. Appears like a resolved globular of low concentration class. Includes a couple of dozen mag 13.5-14.5 stars along with a rich carpet of fainter mag 15 stars. There are several close pairs (1"-2" and possibly closer) and the number of stars keep increasing in moments of rock steady seeing as they seem to emerge from the background. A single brighter star is at the east edge.

17.5" (2/8/86): 30-35 stars resolved, unusually rich, compact, about 5' diameter. The appearance is similar to a resolved globular cluster. Located 30' SW of M35.

13.1" (2/16/85): at least 20-25 stars resolved at 415x.

13.1" (11/5/83): ~15-20 stars, mottled clump near SE edge.

8": few stars resolved over haze.

80mm (1/20/07): visible in the finder at 13x as a very faint, small glow about a half-degree SW of M35.


Thanks for the reports in a variety of scopes. I have not yet seen it well yet, only tried in an 8" dob from a 'Red' zone so far though.

#10 Madratter

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Posted 25 January 2013 - 09:43 AM

In an 8" SCT, "At 140x obviously a star cluster and not a nebula. Partially resolved. Perhaps 1 dozen stars glimpsed with averted at limit of visibility. Very nice."

In a 20" on a day with a full Moon, "20 stars seen on unresolved haze at 360x."

Skies at my site were around 6.0 to slightly better without the Moon in the sky.

#11 galaxyman

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Posted 25 January 2013 - 11:51 AM

With my 4" refractor a couple stars are seen.

In the 6" refractor about a dozen stars or so are seen.

In my 8" refractor dozens of stars are easily seen, resolving much of the cluster.


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#12 Feidb

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Posted 26 January 2013 - 01:42 AM

The last time I saw it was with my home-built 16-inch f/6.4 at 70X. It was a milky haze at the edge of M-35. I didn't resolve any stars because of the low magnification. However, it was obviously a cluster and not a nebula so I must've noticed a grainy texture. I also noted that it was not dense enough or shaped quite right to be a globular. Sometime afterward I added it to my list of Collinder objects, #81.

#13 Scanning4Comets

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Posted 28 January 2013 - 07:14 PM

In my light polluted yard, 2158 is like a puff of light no matter what, unless we get one of those "magically clear nights". From the darker site I frequent, I put anywhere from 160x-240x on it and it looks really nice in my 10" F/4.7

Cheers,

#14 nytecam

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Posted 31 January 2013 - 11:31 AM

revisited last night as below :grin:

Attached Files



#15 blb

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Posted 31 January 2013 - 11:56 AM

Wow Nytecam, I never realized how much this cluster looked like a globular cluster untill I looked at your picture. I have never seen more than about a dozen stars over a hazy spot with my 10" dob.

#16 Achernar

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Posted 31 January 2013 - 11:34 PM

Just tonight I looked at NGC-2158 with my 15-inch from the driveway. To my surprise, some stars were resolved despite the milky skies and a streetlight across from my house. So it appears NGC-2158 is not quite as hard to resolve as I thought. It showed up quite nicely at 227X.


Taras

#17 nytecam

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Posted 01 February 2013 - 04:05 AM

Nice ob Taras :bow:
As you say Buddy, 2158 is very 'globular-like' and to me is very much like GC M71 in Sagitta - if smaller. I suspect some brighter foreground stars overlay 2158 sw of the core :question:

#18 Achernar

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Posted 01 February 2013 - 10:05 AM

Thanks Nytecam, and that is a nice photo you took of this object too. If the weather co-operates tommorow, I'm going to take the 15-inch to an airstrip in the countryside and look at NGC-2158 again. The last time I looked at it before I finished the 15-inch, it resembled a elliptical galaxy or faint comet with no sign of stars being resolved at all. At home I could see stars glimmering at the edge of visibility but the seeing was as always during the winter, poor. I'm sure the view can't help but improve from a much less light polluted area. NGC-2158 like NGC-752, NGC-7789, M-67 and NGC-188 is a very old and massive open cluster, intermediate between the globulars and most open clusters in age. I think it's age is something like 800 million to a billion years old, ancient indeed for an open cluster, but nowhere near as old as NGC-188 or M-67.

Taras

#19 deepskydarrell

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Posted 01 February 2013 - 12:46 PM

That nice Nytecam shot reminded me of 7789 as well. So I looked it up in Urano Deep Sky Field Guide:
2158 Mag 8.6; 5'; 973 stars; brightest star: mag 15.0
7789 Mag 6.7; 25'; 583 Stars; Brightest star: mag 10.0

for what it's worth.

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#20 Special Ed

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Posted 01 February 2013 - 06:06 PM

Just tonight I looked at NGC-2158 with my 15-inch from the driveway. To my surprise, some stars were resolved despite the milky skies and a streetlight across from my house. So it appears NGC-2158 is not quite as hard to resolve as I thought. It showed up quite nicely at 227X.


Taras


Thanks for the report. As Luna wanes, I'm curious as to what I'll be able to see with my 14" and dark Appalachian skies (if the Alberta Clippers ever leave us alone here).






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