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Old 01-03-2018, 10:46 AM
LewisM
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Dust motes POST-PROCESSING

I took some shots of the Fox Fur Nebula, and forgot to retake my flats (changed the filter arrangement etc). As you can see in the image, large motes, particularly frustrating as they are near the structure itself.

Is there any way to process these out effectively? I cannot merely take new flats and reapply, as again, I changed the setup since these images were taken.

Seeing there is some vignette in the field (interesting since it is an FSQ-85 and an 8300 chip...), I tried the PI techniques, and they worked, but they absolutely annihilated the detail in the neb itself. Anything a bit more selective?

Or just start all over again?

Below is a stack total of 1 hr, with a VERY close by 3/4 Luna...
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  #2  
Old 01-03-2018, 11:11 AM
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Lognic04 (Logan)
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Not sure about the dust, but have you tried manually placing dbe points where there is absolutely no dust? I check with deep sky survey data (aladin)
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Old 01-03-2018, 11:34 AM
LewisM
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Logan, I did - that image is post-DBE unfortunately.

I think I'll mark this set of data up as unrecoverable and a learning experience!
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Old 01-03-2018, 12:48 PM
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Lognic04 (Logan)
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Are you sure you are using the divide option, as what you are basically doing to remove vignetting is making an artificial flat.
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Old 01-03-2018, 01:27 PM
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RickS (Rick)
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Here's a (somewhat complicated) way to make a synthetic flat: http://trappedphotons.com/blog/?p=756 There might be some useful ideas in there.

I have managed to repair a variety of image issues by messing around with RangeSelection, PixelMath, Convolution, CloneStamp and the wonderful SubstituteWithPreview script. It's always possible but usually requires some experimentation.

Cheers,
Rick.
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Old 01-03-2018, 05:51 PM
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OzEclipse (Joe Cali)
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Lewis

Won't help with what you've already taken, but why don't you clean the sensor?

I can help you out. I have an air compressor, Joe can blow!

Joe
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Old 01-03-2018, 07:49 PM
LewisM
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Quote:
Originally Posted by OzEclipse View Post
Lewis

Won't help with what you've already taken, but why don't you clean the sensor?
Already done that - that's why I can't redo flats because with cleaned filters and CCD platen, it won't help. Plus they have been repositioned too.

Quote:
Originally Posted by OzEclipse View Post
Joe can blow!

Joe
That's...kind...of...disturbing... Joe....

(actually, I have my own air compressors [x2], being a keen airbrush painter and hobbyist)
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Old 01-03-2018, 11:48 PM
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Steffen
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Dust motes. What we will tell our grandchildren when they ask how we first learned about the alien invasion...
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