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Waxing Gibbous 79.7%
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09-08-2008, 09:03 PM
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Billions and Billions ...
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Join Date: Mar 2007
Location: Quialigo, NSW
Posts: 3,141
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NGC 6188 & friends
Thought I’d do some more wide field work with my 645 reducer. It gives a nice flat 2.4 deg FOV @ F 5.5. This is a 6hr LHaRGB image (60, 120, 60, 60, 60 minutes).
It’s a very pretty field with rich reds, some blues and a multitude of yellow stars. I used 10min subs for the LRGB channels and 20 mins for Ha. I blended the L and the R channels each with Ha in the ratio of 1 to 4 before building the final colour image. I also did an RGB combine and overlaid RGB stars (no Ha) as a colour layer to ensure rich star colours.
I’m pretty sure I’ve got the overall colours right and hopefully it’s not too saturated – it looks good on my CRT.
I cropped it just a tad for composition purposes and opted for the vertical presentation because it somehow looks better. NGC 6164-5 is a nice little bonus in the bottom left corner
Small: http://www.pbase.com/image/101394929/large
Large (full res, 4M) : http://www.pbase.com/image/101394929/original
Cheers, Marcus
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09-08-2008, 09:19 PM
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Galaxy hitchhiking guide
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Join Date: Dec 2007
Location: The Shire
Posts: 8,106
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Marcus!
Pretty cool. Great subject matter, nice framing, guiding spot on. But the cyan rings (due H-alpha layering?) are not so cool.
I suspect A+ data is there, you just need a few tweaks to get the image processing to match.
Regards
Peter
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09-08-2008, 10:38 PM
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Billions and Billions ...
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Join Date: Mar 2007
Location: Quialigo, NSW
Posts: 3,141
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Doh!! Thanks Peter. Yep, still not the Ha blending expert - plus my star layer's colour balance was out. Must have cyan circles under my eyes!
I've tweaked it - a bit better now I think (?). I'll look again when my eyes are clearer.
Cheers, Marcus
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09-08-2008, 11:24 PM
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Highest Observatory in Oz
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Join Date: May 2006
Location: Canberra
Posts: 17,174
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I agree, this is a great orientation for this nebula. It is quite a dramatic presentation, nice work!
This version looks to have no problems with any cyan halos that I can see..? Is Peter being mr picky and tough again
Great to see you having the cohonas to post a full size version but in this case and as good as the image is, I feel it doesn't really do the image any favours. In my opinion, generally a nebula image is usually best appreciated without having to do too much scrolling, you need to be able to take it all in, more in one go or with minimal scrolling at original size and the "large" size in Pbase is always too small. You might like to consider trying a display of say 1600 X 1000 (or just slightly bigger?) for the "original" file size in Pbase for this image? Just a thought.
Again, a really lovely image, very well done!
Mike
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10-08-2008, 12:01 AM
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Billions and Billions ...
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Join Date: Mar 2007
Location: Quialigo, NSW
Posts: 3,141
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Quote:
Originally Posted by strongmanmike
I agree, this is a great orientation for this nebula. It is quite a dramatic presentation, nice work!
This version looks to have no problems with any cyan halos that I can see..? Is Peter being mr picky and tough again
Great to see you having the cohonas to post a full size version but in this case and as good as the image is, I feel it doesn't really do the image any favours. In my opinion, generally a nebula image is usually best appreciated without having to do too much scrolling, you need to be able to take it all in, more in one go or with minimal scrolling at original size and the "large" size in Pbase is always too small. You might like to consider trying a display of say 1600 X 1000 (or just slightly bigger?) for the "original" file size in Pbase for this image? Just a thought.
Again, a really lovely image, very well done!
Mike
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Thanks Mike! Yep, pretty pleased with it myself. The 150 at F5.5 is gem!
Yeah, Peter keeps everyone on their toes (as do you and Jase). I think I've fixed the cyan haloing reasonably well though - especially if you can't fault it!
I was going to post a scaled version but then I thought it's easier just to zoom out in your browser to 50% or so.
Cheers, Marcus
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11-08-2008, 02:52 PM
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Registered User
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Join Date: Sep 2006
Location: Melbourne, Victoria
Posts: 3,916
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Enjoy the composition of this target Marcus. The Ha RGB blend takes practice...certainly to get the deep reds coming through, but in a subtle manner. You could always relayer a basic LRGB or even RGB over the top as PS colour blend mode to manage the star colours. I perceive two items with this image that don't appear right IMO. The Ha in the Ha+R blend is too high. The R channel dominates the histogram. Secondly, I sense this image is lacking resolution from the Ha data. The primary knots of nebulosity are not as pronounced as I would expect from the TOA-150. You'll probably find that a Ha+L blend isn't necessary as the luminance will stand on its own accord as another luminance layer in PS - just alter the opacity to bring the stellar profiles back to match the RGB. That's all the luminance is good if you're blending Ha. You may also find it easier to blend the Ha with a well weighted LRGB. There are many methods to this madness, all delivering a different result. These comments aside, I'm very impressed by FOV with the reducer. Thanks for sharing.
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11-08-2008, 04:29 PM
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Registered User
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Join Date: Feb 2006
Location: Sydney
Posts: 17,896
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Great image Marcus. Really good.
Greg.
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11-08-2008, 08:01 PM
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Registered User
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Join Date: Apr 2007
Location: Penrith NSW
Posts: 159
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Very nice shot... great colour too.
That would look superb printed, I'm sure.
Regards,
Rob
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12-08-2008, 07:07 AM
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Amongst the stars
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Join Date: Jun 2006
Location: Glen Innes, N.S.W.
Posts: 2,867
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That is a beauty Marcus! I nearly missed seeing this lovely image!
Excellent work for sure!
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12-08-2008, 08:32 AM
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Billions and Billions ...
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Join Date: Mar 2007
Location: Quialigo, NSW
Posts: 3,141
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Quote:
Originally Posted by jase
Enjoy the composition of this target Marcus. ...., I'm very impressed by FOV with the reducer. Thanks for sharing.
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Thanks Jase and appreciate your advice too!
Quote:
Originally Posted by gregbradley
Great image Marcus. Really good.
Greg.
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Cheers mate!
Quote:
Originally Posted by robgreaves
Very nice shot... great colour too.
That would look superb printed, I'm sure.
Regards,
Rob
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Thanks Rob! Yes indeed, I print and hang all my images on the wall of my study - this one will make a nice addition. Still plenty of space for more too
Quote:
Originally Posted by Garyh
That is a beauty Marcus! I nearly missed seeing this lovely image!
Excellent work for sure!
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Thanks Gary!
Thanks also to Mike Salway - quite chuffed about having one of my images as image of the week!
Cheers, Marcus
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