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Pal 11 in Aquila

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#1 nytecam

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Posted 03 September 2013 - 04:19 AM

Whilst targetting PN Abell 70 last night [see other post] I also shot for the first time Pal 11 GC also in Aquila in 3m exp. Using Sloan DSS for reference only the consistant faint background stars within the circle are probably GC members - the brighter stars are probably foreground Milky Way stars :grin:
Is Pal 11 a viable visual target :question:

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#2 David Knisely

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Posted 03 September 2013 - 07:50 AM

Yes, Palomar 11 can be seen visually. I managed to see it in a 9.25 inch SCT, although it isn't much to write home about. Clear skies to you.

#3 sgottlieb

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Posted 03 September 2013 - 12:55 PM

This faint cluster is easily visible in my 18-inch and a number of faint stars are resolved, though it's difficult to know if these are all cluster members. The brightest individual members, though, are V = 15.5, so these are likely resolved. Here are some observations back to 1986.

18" (7/14/07): swept up at 150x as a very low surface brightness hazy region, ~3' in diameter with a few mag 15+ stars superimposed. Cradled by three mag 13 stars close southwest, east and northeast. A 22" pair of mag 11.5/12 stars lie ~3.5' N. The observation was interrupted before I could use higher power to resolve.

18" (8/2/05): easily picked up in the field at 115x. At 160x appears as a fairly large, very low surface brightness glow, perhaps 3.5' diameter though the periphery fades into the background and is not easily traced visually. The cluster is nestled adjacent to a group of mag 13 stars and a 22" pair of mag 12 stars is to the north. The surface brightness is irregular or mottled and several extremely faint stars pop in and out of visibility at this power including a few stars near the center. Located 4' SSE of mag 8.6 HD 186496.

18" (7/19/04): at 225x, appears faint, moderately large, round, ~3'-3.5' diameter with almost no central brightening although the globular fades around the periphery. Several faint stars are superimposed. It was difficult to estimate the size as the halo is not well defined. At times I felt the diameter was as large as 6' but sometimes appeared 3' at most. At 435x, a half dozen faint stars are superimposed though some may be foreground stars (the brightest cluster members are mag 15.5). The cluster's surface brightness is quite low at the magnification.

17.5" (8/21/98): visible at 100x as a diffuse, irregular glow 4' SSE of mag 9 SAO 143755 and nestled to the SW of a group of mag 12-14 stars. At 220x, the diameter is 3.5'-4' and the surface appears mottled. Several faint stars were resolved (or superimposed) with averted vision over a ragged glow.

17.5" (7/4/86): faint but easily visible. Appears as a large hazy region best seen at 83x. Some faint stars are superimposed and a nice double star is just N.

#4 uwe_glahn

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Posted 03 September 2013 - 04:30 PM

Wonderful picture of an obscure GC.

And yes, like David and Steve said it is visible and one of the more simpler ones of the Palomar catalog. I tried to translate my Palomar GC project into English, sorry for the bad phrasing.

From the project about Pal 11 I have 4 observations with different aperture:

16", 257x, fst 7m+
faint, circular, also visible with higher power, 3 stars glimpsed through the halo, no other structure

20", fst 7m+
bright, can easily seen with lower magnification, with higher magnification a dozen of stars can be seen

24", fst 7m0
bright, circular, spectacular resolution into a couple of dozens of stars

27", 293x, fst 7m+
bright and remarkably glow; without an clearly concentration; with 293x a dozen stars pops out the mottled glow; brightest stars form a square figure near the middle of the GC

#5 kfiscus

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Posted 03 September 2013 - 10:27 PM

Thank you, Nytecam for another neat capture. I have not done anything with Palomar GCs other than finding and using Pal 8 in Sagittarius to find Pluto. These look to be real retina stretchers.

#6 Bill Weir

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Posted 04 September 2013 - 06:21 PM

All the Pal GCs are visual objects. Between last Sept and this I've observed all of them with my 20". Some were very tough while others were fairly easy.

Bill

#7 kt4hx

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Posted 12 September 2013 - 05:33 PM

I saw it last week with the Z10 during our trip to a dark sky site. At 142x it was just a small fuzzy spot - nothing to get excited about as David said.

#8 JakeSaloranta

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Posted 13 September 2013 - 01:08 AM

3" refractor @ 121x: Extremely faint 2' glow SE from a bright 8th magnitude star. Requires keen averted vision. No detail.

4.5" reflector @ 304x: Fairly faint, round, unresolved, slightly mottled with averted vision? Two/three extremely faint stars visible near the center.

/Jake

#9 Sasa

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Posted 13 September 2013 - 04:48 AM

Nice observations, Jake. I was trying to find it recently from my dark-site place in 110mm refractor, but I had no luck at powers of 40x and 100x. It looks like, from you report, that I will need to try it again and increase the power more.

#10 KidOrion

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Posted 13 September 2013 - 11:12 PM

Went looking for it last weekend with a 12.5 from a Bortle 2 zone. Used Alvin Huey's excellent globular guide and had the spot exactly, but couldn't convince myself that I'd seen it. That same night NGC 6822 and IC 10 were pretty (relatively) easy and NGC 6749 was not terribly difficult; Pal 11 was low, but I thought I should've spotted it. My two cohorts managed to spot M13 naked-eye that evening, so conditions were quite good.

I've seen both Pal 13 and Pal 10 before with a 17.5", but Pal 11 seemed just beyond the reach of the 12.5".

#11 sgottlieb

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Posted 17 September 2013 - 11:48 AM

I took another look at Pal 11 last week with my 24-inch and as expected was able to achieve a better resolution of the cluster than my previous 18-inch observations --

24" (9/7/13): at 200x this relatively bright Palomar globular contained a brighter core and a roundish halo ~2.5' diameter, with several mag 15 and fainter stars resolved. Well resolved at 375x and 500x into roughly two dozen mag 15/16 (several extremely faint) stars resolved in addition to 5 brighter mag 14.5-15 stars. The resolved stars are distributed over the entire glow, though more concentrated in a 1' core that is slightly elongated SW to NE. Situated 4' SE of mag 8.6 HD 186496 with several brighter mag 12-13 stars scattered outside the halo of the cluster.

#12 hokkaido53

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Posted 25 September 2013 - 07:05 AM

I must be doing something wrong. Last night, I searched for Pal 11 for about 5 minutes and couldn't find it, despite using my 18" dob, with ArgoNavis. It's about 9th magnitude, from what I've read, but it must be quite small, so that it appears more like a star than a cluster?

Roy in Taos.

#13 Achernar

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Posted 25 September 2013 - 08:54 AM

It's tough, but possible to observer visually if you have dark skies and a large telescope. Even then, I was not able to see it from the Gulf Coast region of the U.S. even with a 15-inch. If you find it, it will be a dim, unresolved glow, like all of the other Palomar globular clusters. They are challenge objects, but nothing like the showpieces M-22 or M-13 are.

Taras

#14 hokkaido53

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Posted 25 September 2013 - 11:01 AM

It's tough, but possible to observer visually if you have dark skies and a large telescope. Even then, I was not able to see it from the Gulf Coast region of the U.S. even with a 15-inch. If you find it, it will be a dim, unresolved glow, like all of the other Palomar globular clusters. They are challenge objects, but nothing like the showpieces M-22 or M-13 are.

Taras


I think I was looking for the wrong thing - a tight ball of stars. If it appears as just a dim glow, then I probably saw it but didn't recognize it as a globular cluster.

Roy






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