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Tommaso Dorigo
super member
Reged: 03/08/06
Posts: 116
Loc: Venice, Italy and Chicago, Ill...
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Hey Edz,
I was out with my 16" dob a couple of weeks ago, and was amazed to be able to spot NGC7331 with 7x50 binoculars.
We were in a supposedly "dark" site, but the background mag was measured at 20.5, so maybe not that dark after all.
I wonder how many of you bino addicts have tried NGC7331 (the bigger of the Deer Lick Group, in PEG, close to Stephan's quintet) with binoculars. In just a pair of 7x50 it looked amazing.
Cheers,
T.
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Visit me at http://dorigo.wordpress.com
Edited by EdZ (08/10/06 06:05 AM)
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12341
Loc: Cumberland, R I , USA42N71.4W
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Hi Tommaso,
it's been a while, eh?
Never tried 7331, but because it's fairly compact, it has a high surface brightness or Sb13.5, so might not be to bad. It's 11'x4'.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
Edited by EdZ (08/10/06 06:05 AM)
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Phillip Creed
Idiot Seeking Village
Reged: 07/25/06
Posts: 1006
Loc: NE Ohio
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Ed,
By all means, go for it. I usually observe from sites that are NLM 6+, and in all of them NGC 7331 shows up without too much difficulty in an 8x50 finder for my Dobsonian. A pair of 60+mm binoculars from a NLM-5.5 sky should do the trick.
Ed and Tomasso,
The discussion of NGC 7331 and its environs brings an interesting thought into this insane brain of mine. Can any of Stephen's Quintet be spotted with 80mm+ binoculars from a really, REALLY dark sky? The brightest member is NGC 7320, mag~12.7, Sb~12.9 (c/o NSOG). There'll all pretty faint, but they're all relatively compact, each spanning about the same amount of sky as Jupiter, and none has a Sb below 14. Would any of the Stephen's Quintet galaxies be a worthwile objects to add to a Binocular "O'Meara" List, or would they require "averted imagination"?
Clear Skies,
Phil
--------------------
"Why suffer from insanity when you can revel in it?"
Wilderness Center Astronomy Club member since 1995
ICQ Comet Observer Code: CRE01
*****
16" f/4.5 Truss Dobsonian
Orion 120mm ST Refractor
23mm Axiom LX
13mm Ethos (FOR SALE!)
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9mm Nagler Type 6
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*****
Edited by EdZ (08/10/06 06:06 AM)
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12341
Loc: Cumberland, R I , USA42N71.4W
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Quote:
The brightest member is NGC 7320, mag~12.7, Sb~12.9
Well M76 is 3x larger and 10x brighter and is barely visible as starlike in 15x70s
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
Edited by EdZ (08/10/06 06:07 AM)
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Phillip Creed
Idiot Seeking Village
Reged: 07/25/06
Posts: 1006
Loc: NE Ohio
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M76 is a tough one. I was just able to fish that out of a 5.5-NLM sky near Massillon, OH, when I first got my 16x80 Orions.
I'm under NO illusions it would be easy to get an object as faint as NGC 7320, stellar or not, in a pair of 100s. But after seeing NGC 6207 (mag~11.6, Sb~12.6) from a 6.2-NLM site with 25x100s, I just have to wonder if it's possible to grab another small galaxy that's a mag fainter from a NLM 7 site. The optimist in me knows I can find sites that dark within several hours, but the realist in me says that the 4mm exit pupil has already enhanced sky contrast and I'll be getting diminishing marginal rates of return.
For a swinging-for-the-fences task as insane as NGC 7320, I'm guessing either a Cherry Springs sky or better is an absolute minimum, along with 20x+ and/or 90mm+ glasses to differentiate it from background stars, at least an hour of total dark adaption (even going without the red flashlight to look at a chart) and I'm quite frankly not sure that's enough.
Clear Skies,
Phil
--------------------
"Why suffer from insanity when you can revel in it?"
Wilderness Center Astronomy Club member since 1995
ICQ Comet Observer Code: CRE01
*****
16" f/4.5 Truss Dobsonian
Orion 120mm ST Refractor
23mm Axiom LX
13mm Ethos (FOR SALE!)
13mm Nagler Type 6
9mm Nagler Type 6
1.75X Siebert Barlow
*****
Edited by EdZ (08/10/06 06:08 AM)
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12341
Loc: Cumberland, R I , USA42N71.4W
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The NGC database lists 7320 as the brightest of the Quintet, however, it is listed as Sb=13.5. Size is 2.2'x1.1' or only 2.4 sq arcmin. The observing notes that accompany the NGC state it does have a brighter core, but go on to say in 8" extremely faint, small; in 6" marginal but at moments glimpsed at 115x.
For comparison NGC 6207 near M13 is 3x1.4' or 4.2sq arcmin and has Sb of 12.9 with a bright stellar nucleus.
NGC 7331 north of Stephan's Quintet is 39 sq arcmin and Sb is 13.3, but it has a very bright elongated core, so a smaller portion would appear much brighter than Sb13.3.
Interesting to note, NGC7320 and the other four galaxy members of the quintet all fit in an area less than one half the size of NGC 7331.
edz
--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
Edited by EdZ (08/10/06 06:06 AM)
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12341
Loc: Cumberland, R I , USA42N71.4W
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Prompted by Tommaso, I was out last night and tried for 7331. I followed a starhop down thru Lacerta and spent a good deal of time right on this spot, but could not see NGC 7331. However, it was full moon, even though it was blocked from my view, the sky was quite bright.
I had three binoculars outside, Oberwerk 10x60, 15x70 and 25x100. As a starting point, prompted by Sarah's recent report, I stopped by to view 7209 and 7243, two open clusters in Lacerta. 7243, you need to know you are looking at a cluster , it appears so loose. 7209 stars are much fainter and it was hampered by the bright moon. It's sort of like 7789 in Cas. It was difficult to see anything in the 10x60s, the view was so bright. The 25x100 was best. I also stopped to view the 5 component multiple 8 Lac.
While in the area I jumped over to try the planetary nebula NGC 7662, the Blue Snowball, in Andromeda. To me, it seems much easier to get to it from Lacerta. In 15x70 it could just be suspected as something appears a little different about that spot. In 25x100, it was an obvious extended object, although still very small. In 10x60 it could not be differentiated from a star. In fact, until I saw it at 25x100, in the 10x60s I couldn't tell which object it was. A variety of sources list the diameter as 12", 20" 28" and 32"? I did not see any blue color.
Now that I have refreshed my way around this area, I'll try again in a few days for NGC 7331. I suspect without the moon in the sky it should be visible.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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Phillip Creed
Idiot Seeking Village
Reged: 07/25/06
Posts: 1006
Loc: NE Ohio
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Quote:
The NGC database lists 7320 as the brightest of the Quintet, however, it is listed as Sb=13.5. Size is 2.2'x1.1' or only 2.4 sq arcmin. The observing notes that accompany the NGC state it does have a brighter core, but go on to say in 8" extremely faint, small; in 6" marginal but at moments glimpsed at 115x.
Ed,
I looked at this website; I believe Steve Gottleib was providing the description and that he was in Arizona. I'm not sure about his location and sky-darkness, but I think it's safe to say my more darker, more remote observing sites (Cherry Springs; Calhoun County, WV; Spruce Knob, WV) are MAYBE as dark as the typical Arizona "local" dark-sky spot. Sounds like an impossible task for any of Stephen's Quintet's members with 100mm binoculars 
Oh, well. Keep up the good work. Again, I regret not joining Cloudy Nights even a few days earlier than I did; reading your article on giant bino mounts would have yielded a little less in the way of vibrations on my end.
Clear Skies,
Phil
--------------------
"Why suffer from insanity when you can revel in it?"
Wilderness Center Astronomy Club member since 1995
ICQ Comet Observer Code: CRE01
*****
16" f/4.5 Truss Dobsonian
Orion 120mm ST Refractor
23mm Axiom LX
13mm Ethos (FOR SALE!)
13mm Nagler Type 6
9mm Nagler Type 6
1.75X Siebert Barlow
*****
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