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  #1  
Old 17-05-2009, 09:30 AM
TrevorW
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M83 Reprocessed Opinions

I had another go using different flats here are two reprocessed versions

How do you consider they compare to my previously posted image and which do you prefer

Thanks

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  #2  
Old 17-05-2009, 09:59 AM
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jjjnettie (Jeanette)
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It's hard isn't it, trying to get the perfect balance.
Personally I like the first image. It shows more detail of the galactic arms.
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  #3  
Old 17-05-2009, 10:01 AM
tornado33
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Yes I like the first one too. Shows the red H2 regions well too!
Scott
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  #4  
Old 17-05-2009, 10:28 AM
dpastern (Dave Pastern)
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Both seem pretty good to my inexperienced eyes, but I agree with the others - #1 as it shows more of the subtle details in the arm structure. Was this taken with the new RC?

Dave
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  #5  
Old 17-05-2009, 10:51 AM
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I'm not an imager so I dont really know what I am talking about... but...

....I see what the other critiquers mean about the improved 'detail' in number one...but to my untrained and inexperienced eyes the resolution of the details included in the 1st image is decreased (spatial resolution that is); some of the finer parts of the image look slightly bloated to me. Although there are 'more details to see' in the first image, I personally prefer the second as there seems to be less artefact (noise) and it is crisper. The faint fuzzy is fuzzier in the 1st.


Cheers, Kerrie

Last edited by BerrieK; 17-05-2009 at 11:10 AM.
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  #6  
Old 17-05-2009, 11:54 AM
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vash (Ashley)
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I think apart from a little too much red in the galaxy the rest is near spot on, nice flat background not clipped.

I think this one is better just need to take the smallest amount of red out and balance the colour a little more and it will look way better. Another thing, you haven't over sharpened this one as much which is how I like my images, the stars appear smother and have more colour in them, where as your first image was over sharpend.

Last edited by vash; 17-05-2009 at 12:26 PM.
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  #7  
Old 17-05-2009, 04:08 PM
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multiweb (Marc)
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First one's nice. You can use the shadow/highlight tool in PS to tone down the core if you use photoshop. Good pic. Great details.
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  #8  
Old 17-05-2009, 07:50 PM
TrevorW
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Thanks for the feedback
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  #9  
Old 17-05-2009, 08:07 PM
bloodhound31
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Yep, first one's got my vote.

Nice pic too!

Baz.
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  #10  
Old 17-05-2009, 08:58 PM
Alchemy (Clive)
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the darker of the two, the other one has not added to the detail rather has highlighted the noise in the background which detracts from the image also there appears a definite band around the perimeter rather than it fading ito obscurity. there are a couple of tricks to improve the sky background involving getting a less processed version, and using a blend to replace just the background and leave the stars and nebulosity intact, the less processed one has to have the background a smiiiidge lighter than the stretched processed on then blend using lighten, its a very fine line to getting it right so that it cant be detected. as its all the original data its fair game.

this effort is much more even accross the images compared to your first post, a definite improvement.

i sometimes will get a hubble image or an extremely good one and get an idea of just what is actually there, sometimes you can enhance detail that actually is not there it could be noise or something else..... give you an example, i imaged the crab nebula and it has almost a little bite out of the misty nebulosityover it, i though i had stuffed up with a bit of dirt over it so tried to enhance something that wasnt there. so if you are in doubt check multiple images it works for me, then try to do better than they have.

clive

the loop extending from the left of the galaxy at about 10 oclock ?
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  #11  
Old 17-05-2009, 10:10 PM
TrevorW
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Thanks Clive the loop is a reflection from somewhere we think inside the focuser glad you noticed it I was actually going for the second one myself for exactly the reasons you stated

Cheers
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  #12  
Old 19-05-2009, 01:54 AM
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Definately an improvement on your previous image Trevor

Hope you don't mind I adjusted the colour balance highlights in PS to give you an idea of introducing other tones to your image.

I might have overdone the blue but anyway it gives you an idea of what you can do to change the image to your own taste

Barb


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  #13  
Old 22-05-2009, 09:49 AM
TrevorW
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Thanks Barb the blue looks nice I had another go at stacking with 2x drizzle applied and cropped to center the image. Needs a lot more data to bring out detail I've seen one image with 11 hrs data that really shows the blues and reds

Cheers

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  #14  
Old 22-05-2009, 11:33 AM
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leinad (Dan)
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Nicely done.
Is that curving arc to the left of M83 an internal reflection?
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  #15  
Old 22-05-2009, 11:36 AM
TrevorW
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Quote:
Originally Posted by leinad View Post
Nicely done.
Is that curving arc to the left of M83 an internal reflection?
Yes it's a reflection we thinks caused by the focuser I've got a JMI focuser to use on the scope so next clear night I'll try shooting another galaxy and see if the reflection shows up again.

Cheers
Trevor
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  #16  
Old 22-05-2009, 12:11 PM
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suma126 (Shane)
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I LIKE THE FIRST ONE IT SHOWS LITTLE MORE DETAIL .
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  #17  
Old 22-05-2009, 12:26 PM
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leinad (Dan)
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Not a filter causing it(LP filter)? I wouldn't think that a focuser would cause that. Though I could be wrong.
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  #18  
Old 22-05-2009, 12:37 PM
TrevorW
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Someone else who has the same scope got the same type of reflection in an image when using it on a galaxy

I've used the LP filter before on other scopes and haven't had any reflection present

It'll be a case of trial and error to see if it was the focuser although the subs on this image are the longest I've taken using the 350d

Cheers
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  #19  
Old 22-05-2009, 04:28 PM
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That refection is still a problem even with my new focusor. I am going to investigate further to find out what is causing it. I got some far worse last night when I tried imaging NGC4945. I think it is stars that are on the far edge of the field cause this issue. I saw this effect when I was star testing the telescope.
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