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A few weeks ago I took pictures of the Horsehead Nebula using the following setup and settings:

Canon 550D (Rebel T2i)

Canon 75-300mm f4.0-5.6 at f8.0

50x2min exposures

10 dark frames

20 flat frames

Stacked in DSS using median stack

This is the .fits file straight out of DSS:

Capture2.thumb.JPG.b814644c451ea89e8aa798ef73f6f4f7.JPG

It has some pretty bad coma and halos (especially toward the edges) but there is certainly data there. I perform AutoDev on this image to reveal errors and then start the Wipe Module on it. This, however, is where the problem starts.

Capture.thumb.JPG.e2a3b3cea5a7190fd3f323384a4294a2.JPG

When the Wipe is performed, I get this nasty green glow (and no, it's not a Mask). I cannot seem to get rid of it at all. Some setting can change its size and shape, but it still remains. I can see the nebulosity underneath, but I cannot get to it because the glow.

 

Does anybody have any idea what causes this and how to get rid of it?

 

Thanks for any help you can give,

 

Conor.

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Hi there's a blog I'll add a link to later that steps through a workflow starting with the right DSS settings to use. I'm using the latest startools 1.4 beta version it's very stable I find. I'll add the blog link later.

Edit: spillage has given the link.

There a neat filter that will help correct the chromatic aberration you've got on your image.

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I can't say I've seen anything quite like that before, but you don't mention if you cropped the image before doing the wipe. If there are some stacking artefacts left you can get some poor backgrounds. 

When I do the wipe I use the default settings, rather than selecting specifically gradient, or vignetting etc. What do you do?

You say it isn't a mask but it is very much the mask green. Have you tried selecting 'mask', 'clear', 'invert' before doing the wipe? I note that the mask button is highlighted, but I can't remember if that is normal or whether it means the mask has been selected. I don't have access to ST on this machine.

As an aside, you've a good quantity of data, but if it was me I'd be looking to increase the number of darks significantly. Too few can actually increase the noise in an image, rather than improve it.

Ian

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3 hours ago, The Admiral said:

 I note that the mask button is highlighted, but I can't remember if that is normal or whether it means the mask has been selected. I don't have access to ST on this machine.

Ian

Just checked, "DO" should be highlighted, not "MASK", and I don't know how you get that with the wipe screen. If you click on "MASK" then you are taken to another screen, not the Wipe screen. Hmm. If the mask clear action I mentioned above doesn't work, I wonder whether it might be worth trying to download the software again. I presume that you are still using it in trial mode?

Ian

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