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Astrophotography and Sketching >> CCD Imaging & Processing

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gezak22
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Loc: On far side of moon. Send help...
Jones Emberson 1 (with processing question)
      #5538867 - 11/25/12 02:42 PM

Hey guys,

While I have a weakness for off the beaten path objects, I had to play it safe this weekend because of the moon. So I just stuck to a bright target with with sufficient separation from the moon.

Jones Emberson 1

In the processed image, a very clear gradient remains. To me, the left and right edges look much brighter than the center. I don't think this is cosmic fluff. Any ideas where this might be coming from? I don't see anything unusual in the raw images/flats. How would I go about removing this? I only have DSS and PS CS5. Noel Carboni's 'banding' action, didn't remove this.

Thanks for looking/commenting.

EDIT: I'm grabbing some darks right now to see if that takes care of things.

Edit2: A single dark frame resolved the issue. I'll take a couple more to perfect it, but the problem is resolved.

Edited by gezak22 (11/25/12 03:50 PM)


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zerro1
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Reged: 08/02/09

Loc: Smokey Point , 48.12°N 122.25...
Re: Jones Emberson 1 (with processing question) new [Re: gezak22]
      #5538919 - 11/25/12 03:08 PM

It kinda looks like flats are the source to me. GradientXterminator gets rid of most of it. That said, it's been my own experience that flats can introduce gradients that are harder to get rid of than any induced by LP or the moon.

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gezak22
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Reged: 08/15/04

Loc: On far side of moon. Send help...
Re: Jones Emberson 1 (with processing question) new [Re: zerro1]
      #5538963 - 11/25/12 03:26 PM

Quote:

It kinda looks like flats are the source to me. GradientXterminator gets rid of most of it. That said, it's been my own experience that flats can introduce gradients that are harder to get rid of than any induced by LP or the moon.




That was my first guess too. During the first process run, I used old flats. When I retook the flats, I still got the same gradient. None of my previous images show gradients as obvious as this one in my opinion.

Anyway, if darks don't solve this, I might just spring for a copy of the xterminator.


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bill w
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Re: Jones Emberson 1 (with processing question) new [Re: gezak22]
      #5539548 - 11/25/12 10:38 PM

nice shot
gradient xterminator is great
would hardly call this a bright one
usually takes large aperture and dark skies to see it visually


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gezak22
professor emeritus
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Reged: 08/15/04

Loc: On far side of moon. Send help...
Re: Jones Emberson 1 (with processing question) new [Re: bill w]
      #5539695 - 11/26/12 12:55 AM

Quote:

nice shot
gradient xterminator is great
would hardly call this a bright one
usually takes large aperture and dark skies to see it visually




Thanks Bill. I have to say that photographically, JE1 is a pretty bright PN. I was able to bag it with my 200 mm f2.8 telephoto lens + DSLR combo. But because it was so small, I didn't think it was worth a full session back then. Now, with my 90 mm scope and a mono CCD, this target is a no-issue, even under a full moon.

As for gradientxterminator, I'll buy it once I need it. As long as I have access to reasonably dark skies, I shouldn't have to deal with gradients unless I screw something up during image processing.


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David PavlichAdministrator
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Re: Jones Emberson 1 (with processing question) new [Re: gezak22]
      #5540605 - 11/26/12 04:21 PM

This is a nice image! I'd like to see it from someone with a long focal length scope to get a bit better image scale. Rick and his 14" Meade would be good.

David


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bill w
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Reged: 03/26/05

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Re: Jones Emberson 1 (with processing question) new [Re: David Pavlich]
      #5540694 - 11/26/12 05:22 PM

Quote:

This is a nice image! I'd like to see it from someone with a long focal length scope to get a bit better image scale. Rick and his 14" Meade would be good.

David



not to steal his thunder, but rick j shot it a few years ago and reposted at the bottom of this thread


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gezak22
professor emeritus
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Reged: 08/15/04

Loc: On far side of moon. Send help...
Re: Jones Emberson 1 (with processing question) new [Re: bill w]
      #5541451 - 11/27/12 01:48 AM

Quote:

Quote:

This is a nice image! I'd like to see it from someone with a long focal length scope to get a bit better image scale. Rick and his 14" Meade would be good.

David



not to steal his thunder, but rick j shot it a few years ago and reposted at the bottom of this thread




No worries, I see nothing wrong with some reference images. As a widefield junkie I prefer the shorter fl images, though I admit they are not that demanding on the equipment.


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David PavlichAdministrator
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Re: Jones Emberson 1 (with processing question) new [Re: bill w]
      #5541718 - 11/27/12 09:30 AM

Quote:

Quote:

This is a nice image! I'd like to see it from someone with a long focal length scope to get a bit better image scale. Rick and his 14" Meade would be good.

David



not to steal his thunder, but rick j shot it a few years ago and reposted at the bottom of this thread




Thanks for posting the link!

David


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