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Old 27-07-2011, 01:23 PM
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Paddy (Patrick)
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A few Globulars and an OC 22/7/11

Had a little observing through moist skies last Friday. Transparency was poor, so I thought "GCs" and still included a couple of fainter ones.

Here are my notes.

Telescope 410mm (16”) f4.9 tri-dob reflector
Eyepieces 28mm UWAN, 17,13,9 mm Naglers, Paracorr
Navigation: Night Sky Observer’s Guide (NSOG), Uranometria Vol 2
Data from NGC/IC project, SEDS list of galactic GCs, http://seds.org/messier/xtra/supp/mw_gc.html

2030

Seeing good, transparency fair – lots of high altitude moisture so bright stars have something of a halo

Lynga 7 GC in Norma
16:11:03.65 -55:19:04.0
Vmag 10.8

175X Next to a bright foreground star and y shaped asterism. This faint haze is just discernible against the busy background sky. Is quite round and looks about 3’ across.

(notes from SEDS http://spider.seds.org/spider/MWGC/lynga7.html
Discovered 1964 by G. Lynga.
Recognized as globular cluster in 1993 by Ortolani, Bica and Barbuy.

Globular cluster Lynga 7 was first cataloged by G. Lynga (1964) as open cluster and classified as of Trumpler type II 2 p. It is listed again as open cluster by van den Bergh-Hagen (1975) as vdB-Ha 184.

It was only in 1993 that Ortolani, Bica and Barbuy brought up evidence that this object might be a globular cluster. They investigated its color-magnitude diagram, which resembles that of a globular, but derive a significantly lower age than for the usual globular clusters, and classify it as a disk globular cluster. Similar results were obtained by Tavarez and Friel (1995). Meanwhile, Lynga 7 is generally regarded as globular.

Lynga 7 is one of the more "metal-rich" globulars, i.e. its stars contain significantly higher concentrations of elements heavier than Helium than average globulars, more similar to the composition of our Sun.

NGC 6067 OC in Norma Trumpler class I 3 r
16h 13m 11.0s -54º 13' 06"
Vmag 5.6 Dia 12’

135X Just the other side of Kappa Normae from Lynga 7, this is a very distinct spray of about 100 stars with a very nice bright pair right in the middle and lots of interesting lines and asterisms. The brightest of the pair is yellowish and the slightly fainter partner is blue. Quite a bit of variation in stellar magnitudes, but none that are really bright. Elongated p-f and stands out well against the star field and is quite obvious in the finderscope. In the centre is a starfish-shaped dark patch.


Pismis 26 GC in Scorpius
17:36:10.5 -38:33:12
Vmag 12.2 Dia 2.2’

175X A faintly discernible circle of haze sitting in a little triangle of stars about 2’ dia.

NGC 6544 GC in Sagittarius Class V
8h 07m 20.5s -24º 59' 51"
Vmag 7.5 Dia. 8.9

175X Quite a pretty GC moderately concentrated in a busy field with some stars just resolvable and many on the edge of resolution. On the preceding side is a N-S arc of stars (convex preceding) and another to the following side. So the star field is quite beautiful, but it’s a little hard to find the edge of the GC amongst it.

A tad over 1’ to the east is

NGC 6553 GC in Sagittarius Class II
18h 09m 17.5s -25º 54' 28"
Vmag 8.3 Dia 9.2

175X Looks a little larger to my eye than neighbouring 6544 and in a quieter field. There is a bright star at the preceding edge. The GCs glow is very even, very round with no marked core but overall very concentrated with no resolved stars.
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Old 27-07-2011, 06:36 PM
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ngcles
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Hi Paddy & All,

Thanks for taking the time to share your observations with us. Good to see someone going after some of the more obscure G.Cs, though at first Pismis 26 had me a bit stumped -- it is better known (to me at least) as Ton 2.

One of the tricks with Ton 2 is to exclude the 4th magnitude star (Q Scorpii) that is just 8-odd arc-mins SE from the cluster and most importantly ... don't look for something that looks like a GC -- look for what seems like a small, LSB face on spiral eg. Here's how it appeared to me back in 1996 with 25cm at x181:

"This cluster is found 7-7.5' to the NW of mag 4.5 Q Scorpii. This must be excluded to permit detection. Extremely !! faint in this apeture, barely there but largish, 2.5' -3' diameter as a weak patch of diaphanous gossamer with no central brightening. Mag 13 * superimposed in the WSW near the edge. Round. Confirmed by G Mitchell."

Your observation of Lynga 7 is remarkably similar to mine from 2000 with 31cm at x186:

"This took some time to pick up in the field. It lies within a Tri formed by a mag 8 *, a mag 9 *, and an inverted "Y" shaped asterism of mag 13-14 *s, which is 5' a side. One or two mag 14-5-15 *s are seen superimposed on the halo. It is hard to believe they are resolved *s. 2' diameter with a weak central brightening and looks like a face on spiral eg of v/lsb. It is probably easier than Vdb-HA 176."

Have you tried for Vdb 176HA (also in Norma) yet Pat?

Best,

Les D
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Old 28-07-2011, 09:57 PM
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michaellxv (Michael)
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Thanks Paddy for the excellent desciptions.
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Old 29-07-2011, 12:11 AM
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mental4astro (Alexander)
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Quote:
Originally Posted by ngcles View Post
diaphanous gossamer

Now there's something you don't read everyday! Brilliant!

Nice work Paddy. Lovely descriptions and I'm impressed with the level of research you've done too.
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Old 29-07-2011, 11:35 AM
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Paddy (Patrick)
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Thanks Les, Michael and Alex. Les our descriptions do sound very similar. Some of these faint GCs are really hard to pick, so I find the DSS images to be essential. I've got Vdb 176HA on my list.
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Old 29-07-2011, 11:19 PM
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Ephemeral

Hi All,

Quote:
Originally Posted by mental4astro View Post
Now there's something you don't read everyday! Brilliant!
Well you do in my observing log! Another word I'm fond of using (and get stirred by my friends for using when recording notes) is "ephemeral". If you don't mix some words in there to give some gradation and shades of meaning, every entry in your log will read like all the others I reckon! English is such a wonderful language but unfortunately in common usage there are some words (over) used a lot like "awesome" but so many others that unless someone nurtures them, will become arcane. I'm here to nurture them!

Quote:
Originally Posted by Paddy View Post
Thanks Les, Michael and Alex. Les our descriptions do sound very similar. Some of these faint GCs are really hard to pick, so I find the DSS images to be essential. I've got Vdb 176HA on my list.
Vdb 176HA is a very, very tough object -- on a par with some of the tougher Terzan and Palomar GC's. In pristine conditions it was *barely* detectable in 31cm. I haven't been back to see it in 46cm. Must do that one day! Sidney Van den Bergh is one of my favourite astronomers. Writes papers that can be read by nearly anyone including dummies like me!


Best,

Les D
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Old 30-07-2011, 11:38 AM
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Paddy (Patrick)
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Quote:
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Sidney Van den Bergh is one of my favourite astronomers. Writes papers that can be read by nearly anyone

Best,

Les D
Now that's appealing. And some of the vdBH open clusters are very pretty to boot!
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Old 05-08-2011, 04:47 PM
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orestis
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Great Stuff Paddy,

Good to see you taking advantage of some aperture and looking at the faint stuff.

there are a lot of globulars around,Always satisfying to observe globs knowing hoe many stars are crammed into a fairly small place on the cosmic scale.

Thanks for posting paddy
Cheers Orestis
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Old 05-08-2011, 05:03 PM
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Excellent stuff Patrick, brilliant, ephemeral and awesome!

Here's a link that might interest you (I expect a full report!):
http://www.astronomy-mall.com/Advent...ce/palglob.htm

Cheers -
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Old 06-08-2011, 12:14 AM
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Hi Rob, Paddy & All,

Quote:
Originally Posted by Rob_K View Post
Here's a link that might interest you (I expect a full report!):
http://www.astronomy-mall.com/Advent...ce/palglob.htm

Cheers -
The Palomar clusters are by-and-large a pretty testy bunch and some are not at all for the faint of heart. I've seen all but three -- Pal 1, Pal 4 and Pal 13. The easiest are Pal 9 and Pal 8 by a distance. There are quite a few NGC G.C's that are easier than Pal 8 -- it is visible in a 4" (Tak 106 FSQ) under a top-notch sky and in my 46cm, shows a few resolved stars. Pal 9 is of course an "error" to the extent that it was already in the NGC list and only added as a "new" cluster by mistake. Pal 6, Pal 15, Pal 3 and Pal 14 are the most difficult I've seen -- particularly 15. 4 and 13 are on my to-do list.

Best of luck with it.


Best,

Les D

Edit: Dunno what caused me to check, but I have in fact seen Pal 13 -- in 31cm too. Only Pal 4 to see of those that are above my horizon. Though Pal 4 is in URSA Major, it is only barely over the border from northern Leo and reaches a reasonable elevation (though far from high). It is higher than Pal 2 in Auriga that was faint but perhaps a little better than expected.

Last edited by ngcles; 06-08-2011 at 02:46 PM.
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Old 06-08-2011, 12:33 AM
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Thanks Les! Pal 7, 8 & 9 are my limit I'm afraid. I did read an observation report once that claimed Pal 9 (NGC 6717) was "a challenging object even in a large aperture scope" but it was quite easy in a 4.5 inch. Tiny fuzzy glow beside a bright star, averted vision not needed. Pal 8 was also relatively easy as a small round dim glow. Pal 7 (IC1276) was much more difficult, large dim very faint glow that was in and out of vision. The only resolving going on was resolving not to attempt any more Pal globular clusters with this scope...

Cheers -
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Old 08-08-2011, 06:05 PM
astrospotter (Mark)
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The Pals are illusive at best

Nice read on the OR Paddy (as usual).

One goal I have had this year (and the last 2 years) has been to attempt to complete the Pal observations in my 18" dob. Pal 15 which is the last Pal of the 15 that I feel 'compelled' to view (somehow) in my 18" scope I feel I may have to say I was unable to see. I certainly was unable to absolutely with certainty say it was viewed. I should say several other pals were very close to the limits but with those I felt certain enough to claim them even though some were down in the 20-30% viewable with averted and scope movement sort of case. I find scope movement really can add that extra edge on the limit.

I can still not say any definite sighting on Pal 15 and I try very hard to not let my averted imagination take hold. This last month brought me to an 8000 foot mountain in 21.74 type SQM skies on a very good night of seeing.

I shrouded my head and closed my eyes for 15-20 minutes (even after already being quite dark adapted by the way).

Still all I can claim is I 'kinda sorta maybe' detected that nasty Pal 15. I am going to leave it at that and not claim it but it was so awfully close I could almost taste it (in a manner of speaking).

so yes, those Pal globs are illusive even in 18" dob on an extremely good night.

I think I'll have to wait and view it in some larger scope like maybe a 24" might do it with confirmed certainty.
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Old 09-08-2011, 02:01 PM
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Paddy (Patrick)
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Thanks all. That Palomar list is an interesting read and another challenge, Rob. I will do my best. Sounds like I shouldn't get too excited about Pal 15. Orestis, your comment about the satisfaction of seeing something with so many stars packed into such a small amount of space it spot on.
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