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Old 24-07-2012, 11:10 AM
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Paddy (Patrick)
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Messier 7 and friends

Well, a brief window of opportunity between clouds saw my scope out for long enough to actually observe. I thought I'dhave a go at the observing challenge. The seeing was good and transparency poor and going for galaxies and fainter objects was pointless. With Scorpius near zenith, Alex's challenge of teasing apart M& and it's friends seemed worth a go. Here is the report.

Scope 16" tri-dob
Charts Uranometria


135x In observing this cluster it is easy to get fixed on the very bright central 25 or so stars which spill out beyond the 40 FOV.These bright stars form a N-S line to the east, a flatted triangle to the west and others are distributed in many interesting asterisms between. NGC 6453 (GC) forms the western apex of a 30 per side equilateral triangle with 2 bright stars at the NW edge of the central group of M7. 6453 is a 4 dia bright unresolved GC with a high degree of concentration and an overlaid triangular asterism. 30 SW of 6453 is NGC 6444, denoted as a star cloud in Uranometria. It consists of 100+ fainter stars arranged in a 15 E-W ridge (crossed by several shorter N-S lines of stars). At the western end of the ridge a 15 ridge of stars projects to the north. Further to the west is a dense haze of background stars. 7 NE of 6453 is a small concentration of stars which is not marked in Uranometria.

Also observed but with insufficient time for notes were NGC 5455 (star cloud) 6437 (star cloud) 6421 (star cloud) Trumpler 30 (OC) and Barnard dark nebulae 286 & 287

With a good chart this is a fascinating area of sky to observe.
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Old 24-07-2012, 11:34 AM
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You describe star fields so absolutely beautifully Paddy!
I don't think I've ever seen a star cloud- I'm excited to tackle some after reading your report.
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Old 26-07-2012, 06:40 AM
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MattT (Matthew)
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Nice report Paddy, going up and down the area with a 4" frac is one of my favourite things so many stars so little time...I was trying to find Centaurus A with my 8" reflector with no luck so changed scopes glad I did.
Matt
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Old 26-07-2012, 02:27 PM
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Paddy (Patrick)
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Thanks Suzy and Matt. The term star cloud is quite interesting - I will have to do a bit of reading again on this and see where the line is drawn between open clusters and star clouds.
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Old 26-07-2012, 03:44 PM
Rob_K
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Quote:
Originally Posted by Paddy View Post
Thanks Suzy and Matt. The term star cloud is quite interesting - I will have to do a bit of reading again on this and see where the line is drawn between open clusters and star clouds.
Open clusters consist of stars that are 'related' to each other, sharing common motion and distance. Incubated together in the same stellar nursery. I don't think (but would happily stand corrected) that dense apparent 'clusters' of stars resulting from chance viewing alignments can be called open clusters. Star cloud simply refers to the apparent density of stars in a region as we peer through our galaxy from Earth - eg the Sagittarius Star Cloud where the incredibly dense 'cloud' consists of stars unrelated to each other and at widely differing distances from Earth.

Great report anyway Patrick!

Cheers -
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Old 26-07-2012, 08:43 PM
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Paddy (Patrick)
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Thanks Rob, that is very helpful. Suzy, if you haven't browsed the Small Sagittarius Star Cloud, Messier 24, it is a fantastic way to spend some time. Lots of stars in interesting patterns and not hard to find naked eye. Will want very low power.
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Old 27-07-2012, 07:51 AM
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Hi Paddy,
No- I haven't explored the Sag. star cloud region before. I've always wondered what a star cloud is, so when you said you were going to find out, I thought oh goody! So thanks Rob for clearing that up.
It's definitely going on my next session to view & thanks for the tip on low power.
As Matt said so well.. so many stars, so little time.

Last edited by Suzy; 27-07-2012 at 11:18 AM. Reason: grammar.
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Old 29-07-2012, 08:33 AM
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kustard (Simon)
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I'm taking your notes with me on my next observation night Patrick because that all sounds fantastic!

I will compare and contrast
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