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Date: 30 Jul 2006 17:04:37
From: Bill Cotten
Subject: Observing Palomar 11
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Hi all,
I have been working on the Astronomical League's Globular Cluster program
off and on for about a year. There is a "challenge list" of objects of which
one (1) is required. "Any" Palomar cluster qualifies. I have decided to
atleast attempt to observe every object on the list visible from my
location. My scope of choice for the project is a Richard Fagin 8" f/6
newt/dob.
Observing conditions at my local site are generally pretty good. M33 and
ngc752 are naked eye on good nights. I first attempted to see Pal 11 last
August 7th when both transparency and steadiness were 8/10. I'm quite
certain I had the right spot as plotted in the latest Uranometria. Using the
8" f/6 with a 22 Panoptic my observation was "Small, extremely faint with
only a very slight "haze" detected using averted vision. No central
condensation. No stars resolved. Not entirely sure I saw it! Higher
magnification did not help."
I went to Oregon Star Party the following month determined to try again. My
second observation with the same scope/ep was identical to my original. I
also used a 14" and 18" scope the same night and the only thing I could add
to the observation was that the "very slight haze" I saw was just a tiny bit
brighter with a fleeting hint of mottling. Conditions at OSP were less than
ideal last year and I thought that conditions at my local site were just a
touch better. Local site is near Fishtrap lake in eastern WA.
I am now seeking observations and opinions from others using a similar size
scope to see what others have experienced. This is by far the most difficult
observation I've ever made and I'd like to be sure my observation was not
"averted imagination".
Cheers,
Bill
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Date: 30 Jul 2006 17:30:14
From: Steve Gottlieb
Subject: Re: Observing Palomar 11
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Here are my last two observations of this cluster with my 18-inch,
though I haven't looked for it in smaller 'scopes --
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 only appeared
3' at best. 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.
Steve Gottlieb
In article <EvSdnYGtnOdr1VDZnZ2dnUVZ_rSdnZ2d@comcast.com >,
"Bill Cotten" <bill_cottenREMOVETHIS@ANDTHIScomcast.net > wrote:
> Hi all,
> I have been working on the Astronomical League's Globular Cluster program
> off and on for about a year. There is a "challenge list" of objects of which
> one (1) is required. "Any" Palomar cluster qualifies. I have decided to
> atleast attempt to observe every object on the list visible from my
> location. My scope of choice for the project is a Richard Fagin 8" f/6
> newt/dob.
>
> Observing conditions at my local site are generally pretty good. M33 and
> ngc752 are naked eye on good nights. I first attempted to see Pal 11 last
> August 7th when both transparency and steadiness were 8/10. I'm quite
> certain I had the right spot as plotted in the latest Uranometria. Using the
> 8" f/6 with a 22 Panoptic my observation was "Small, extremely faint with
> only a very slight "haze" detected using averted vision. No central
> condensation. No stars resolved. Not entirely sure I saw it! Higher
> magnification did not help."
>
> I went to Oregon Star Party the following month determined to try again. My
> second observation with the same scope/ep was identical to my original. I
> also used a 14" and 18" scope the same night and the only thing I could add
> to the observation was that the "very slight haze" I saw was just a tiny bit
> brighter with a fleeting hint of mottling. Conditions at OSP were less than
> ideal last year and I thought that conditions at my local site were just a
> touch better. Local site is near Fishtrap lake in eastern WA.
>
> I am now seeking observations and opinions from others using a similar size
> scope to see what others have experienced. This is by far the most difficult
> observation I've ever made and I'd like to be sure my observation was not
> "averted imagination".
> Cheers,
> Bill
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