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Old 10-06-2007, 12:31 PM
Rob_K
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Obs Report, 9 June 07: Dim globs & dimmer observer!

Spent a really nice evening last night at Porepunkah airfield with a few from our group, plus John ('xstream') & Anna from Albury. Clear night – seeing was poor but transparency OK (but just a little off). Saw lots of good things – usual culprits such as Omega Centauri, Eta Carinae, 47Tuc, Sombrero galaxy etc, and also stuff such as Trifid & Swan nebulae. Great views through Anna’s scope – top eyepieces and excellent detail.

I was tracking down dim globular clusters with my 4½ inch (114x900mm), and came pretty well prepared with print-outs of FOVs generated in Starry Night. Very successful, adding 5 dimmies to my list, now up to 90. John & Anna were very helpful – I’d find the target in my scope and roughly describe what I was seeing and where, and then John would punch in the NGC number in the GOTO, and bring up the object to confirm. Much brighter of course in their scope, and it was really good to check that I wasn’t imagining things! Gives you great confidence in what you’re doing & seeing, given my very small aperture. The globs we observed were:

NGC5053 in Coma Berenices: The most challenging target visually – in my scope seemed large and very diffuse, vv dim and just barely visible in averted vision. Just fitted in FOV with M53, another glob, in 21mm eyepiece. Not all that much better in Anna’s scope. Mag 9.8.
NGC5466 in Bootes: Said to be a challenging target, but quite clear in 4½ inch – dim, fairly diffuse but did not need averted vision. Much brighter in Anna’s scope. Mag 9.1.
NGC5694 in Hydra: This is one of the most distant Milky Way globs. Mag 10.2 but easy to see – very small and starlike, in fact just like a fuzzy star. Anna’s scope brought up a little bit more of the extent.
NGC6235 in Ophiuchus: Mag 10.2 but reasonably easy to see – the proximity of Jupiter threatened to wash this one out, but even with flare due to atmospheric moisture it was still OK. Small, dim with central brightening. Much better in Anna’s scope.
NGC6325 in Ophiuchus: Another Mag 10.2 – reasonably easy, but needed averted vision to see it. Slight central brightening. Much better in Anna’s scope.

Well, that’s about it. Oh, did I mention I lost my car key? Had to be rescued by John & Anna, who gave me a lift home, but had to leave car, scope etc out at the airfield. Went back this morning and found key out in the paddock, and everything safe & secure! Thanks again folks! Nice to meet more IISers, and put faces to names.

Cheers -
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Old 11-06-2007, 02:58 PM
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ballaratdragons (Ken)
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Sounds like a great night Rob! (except losing your key)

Yep, John and Anna are good people
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Old 13-06-2007, 03:08 PM
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xstream (John)
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Nice report Rob. I don't know how I missed this post before.

It was a challenging group of objects you had for 114mm and certainly got the observing skills going. Great stuff!
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Old 16-06-2007, 09:25 AM
Rob_K
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Nice dark skies tonight, Fri 16 June, but seeing poor - lots of star twinkle even at zenith. Flushed with my recent 'success' as outlined above, decided to flush out a few more dim globular clusters with the Tasco (114x900 reflector on Alt/Az mount, using 21mm Celestron X-Cel eyepiece). Saw these:

NGC6366 in Ophiuchus: Very very dim, amorphous largish glow in averted vision, Mag 10.0;
NGC6426 in Ophiuchus: Extremely dim, small glow in averted vision. Appeared round. Popped in and out of vision, and no wonder at mag 11.2, the dimmest glob I have yet seen;
NGC4147 in Coma Berenices: Easy to see – tiny bright fuzzy glow, starlike. Mag 10.3.

Had a quick go at NGC6717 in Sagittarius (mag 8.4 but said to be challenging even in a large scope because of the obscuring starfield) and NGC6256 in Scorpius (mag 11.3), but no go - need to do more work on these to pin down their precise positions in relation to surrounding stars. When you're working with limited aperture on dimmies, you need to know you are staring at the exact spot because there are bits of nebulosity all over the place!

Cheers -
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Old 27-06-2007, 09:45 PM
Rob_K
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I thought I might as well continue this thread with further globular cluster observations, all using Tasco "Space Station" 114x900 reflector, motorised Alt/Az mount, 21mm Celestron X-Cel EP. Hope this is OK, mods. The latest two obs were from my backyard in Bright, around 10pm EST, 16 June 2007.

NGC 6717 (Pal 9) in Sagittarius: Mag 8.4, but said to be "challenging object even for large aperture scope". However, I found it to be relatively easy once I got a decent chart prepared. Tiny fuzzy glow beside brighter star, averted vision not needed.
NGC 6256 in Scorpius: Extremely dim smallish glow in averted vision (mag 11.3!). In and out of vision. As with all really dim objects requiring averted vision, moving the telescope a little backwards and forwards helps to confirm the sighting. V dark skies essential!

Reviewed my glob observations listing, and these two actually take me to 96 observed now, not 95. The only two globs under mag 10 that I haven’t seen yet are M92 (mag 6.5) & NGC 6229 (mag 9.4), both in Hercules. Unfortunately, neither appear to rise above the hilly horizon at my place. I think I might be able to add a few more to my list, but I’m very close to the limit of my capabilities with present gear. More anon…….. I hope!

Cheers -
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Old 28-06-2007, 07:46 AM
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erick (Eric)
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Impressive observing, Rob! Better get to the top of that hilly horizon to nab some more!
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Old 11-07-2007, 10:30 PM
Rob_K
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Continued my "dim globular cluster hunt" at the Bright Astronomy Group’s monthly viewing night at Porepunkah Airfield tonight. Added three more, taking my tally of globs observed to 99 (Tasco ‘Space Station’ 114x900mm reflector with 21mm Celestron X-Cel eyepiece).

IC4499 in Apus - Relatively easy to see – smallish, round faint glow next to brighter star. Averted vision not needed in dark skies. Mag 10.6.
Djorg 2 in Sagittarius - Very faint, very small glow, presumably core of cluster. Mag 9.9 but obscured in starfield. This is one I’d removed from my list of possibles because I assumed it would be too obscured. However, I read some reports of it being visible even to moderate sized scopes.
IC1276 (Pal 7) in Serpens - Very dim, largish amorphous glow in averted vision – in and out of vision. Very difficult and needed very dark skies. Mag 10.3.

Tonight was a very cold night, with frost on ground by 7pm. Only 5 hardy souls showed up, but they were treated to excellent dark skies, with good seeing. Lots on offer – crescent Venus, Saturn heading into the murk, Jupiter with a nice moon alignment, plus heaps of deep sky. 47 Tuc, Omega Centauri, Triffid/Lagoon nebulae, etc. Later, Ring & Dumbbell planetary nebulae had cleared the horizon and gave surprisingly good views. Frozen to the core by 8:30pm and the last of us packed up & headed home to defrost!

Cheers -
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