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Old 25-04-2013, 09:22 AM
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Jon (Jonathan)
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Ngc2808

7x2 min subs, taken last night in full moon. It's a pretty globular, although with darker skies it might have come out differently.
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Old 26-04-2013, 03:39 AM
Vasya Pupkin (Pupkin)
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I am agree with you, excellent photo.
But one question, as for you, can you really distinguish different globulars, they are so similar.
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Old 26-04-2013, 06:18 AM
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Yes, they are. But with subtle differences in the extent to which the stars are compressed and dispersed; how compact they are; the colours in the cluster and the colours in the foreground stars. The longer you spend looking, the more different they seem!

I love globulars. Always have; I guess it was the "wow" factor when I first saw Omega Centauri through a scope.
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Old 26-04-2013, 10:18 AM
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Nice one Jon, I don't know much about Globs but have always wondered if all stars are white or can they have stars at varying temperatures, I don't recall seeing any image with stars of different colours. that would look nice.

as for the image, I'm guessing your focus was a tiny bit off and PA? was it taken with the meade? is it on a wedge?
Globs are pretty much the only objects you can image whether the moon is out or not. Also an excellent test objects for tracking and focus. I'd suggest a Baht Mask. Well done.

Cheers
Alistair
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Old 26-04-2013, 10:46 AM
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Apparently NGc2808 is known for having stars at different stages of the main sequence: most globs consist just of old stars.

Yes, focus was a bit off. I just "snapped" this to show my mother howitzer all worked. PA should have been ok - the Meade is on the Losmandy G11 and the subs were guided - but it was windy and I get a fair bit of flexure between the OTA and guidescope when it's windy. I've got an OAG just recently but am having trouble getting the cameras parfocal.
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Old 26-04-2013, 12:41 PM
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Hi,

Reason I mentioned PA was cause you can makeout a bit of field rotation in the corners.
yes, focusing the OAG guidecam and main camera can be tricky. which OAG do you have? however guiding with the oag will give very good results.

so are there any younger globs where you can see blue and red stars? I'll have to brush on my star phases.

Cheers
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Old 26-04-2013, 05:13 PM
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Hi Jon,
Nice shot. I feel the same way since I first saw Omega Centauri.
Was it taken with the 60Da?
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Old 26-04-2013, 10:18 PM
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Alistair - you are right, there is some field rotation. Must have bumped the tripod after aligning.

Ross - yes, the 6Da, with the Meade SC 10" with a f6.3 focal reducer.
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Old 27-04-2013, 06:48 AM
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Nice to see some glob images! I am a bit obsessed with them so I observe them a lot!
You did a good job not over exposing the core.
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Old 27-04-2013, 08:20 AM
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Cheers Gant. I like 'em too. Because often moonlight,I didn't worry about the faint outliers so concentrated on not blowing out the core.

Alistair, check out this HST photo of 47 Tuc. Colours are really clear. http://www.daviddarling.info/encyclo...7_Tucanae.html. This is an interesting page from the astrophysics course at Durham. http://www.dur.ac.uk/ian.smail/gcCm/...ntro.html#Aims
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Old 03-05-2013, 06:18 PM
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I've addeed a new thread with some more colourful globs
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