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pix insight help discolouring leo triplet

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#1 iwols

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Posted 08 April 2021 - 09:03 AM

Hi all need a lot of advice please added screenshot of the leo triplet but is discoloured,so far ive used weighted batchpreprocessing with darks flats bias then dbe then done a rgb combination but the resulting image is discoloured ,i know ive took a shortcut but what would you do next thanks

 

https://www.dropbox.....58.27.png?dl=0


Edited by iwols, 08 April 2021 - 09:10 AM.


#2 jonnybravo0311

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Posted 08 April 2021 - 09:13 AM

  1. Figure out what those black spots are in your master R, G and B
  2. Figure out what went wrong with your calibration frames (darks, flats, darkFlats and/or bias)
  3. When you start processing, you need to use DynamicCrop to get rid of the stacking artifacts around the edges of the images
  4. Make sure the images are all registered to a single, master frame. Ideally, this should be done during the stacking stage, but you can cheat and do it once all the images are stacked
  5. A combined RGB image is not going to pop out perfectly colored and ready to go. At a minimum you need to do a background neutralization and color calibration. Then, perhaps you might want to do SCNR and some other denoise techniques (MMT, TGVDenoise, etc). There's also HistogramTransformation / arcsinh stretch / masked stretch / curves / hue / saturation / etc.

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#3 Jared

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Posted 08 April 2021 - 09:24 AM

Hi all need a lot of advice please added screenshot of the leo triplet but is discoloured,so far ive used weighted batchpreprocessing with darks flats bias then dbe then done a rgb combination but the resulting image is discoloured ,i know ive took a shortcut but what would you do next thanks

https://www.dropbox.....58.27.png?dl=0


Something is not right in your calibration which is causing the black spots. Pixels are getting clipped to zero. Possible causes would include offset being too low, offset in hour bias or dark frames being different from lights, gain being different between lights and calibration files, bias being subtracted twice. Lots of possibilities.

Second, after registration and stacking but before DBE you do want to apply the exact same crop to all your subs or DBE (especially with auto-placed samples) will not work properly.

Third is your actual question—the color imbalance. This is totally normal. Some combination of light pollution gradients and different sensitivities through different filters. There are two common approaches. The first is to use background neutralization and color calibration. The second option—even better—is to use photometric color calibration with background neutralization enabled.

After all this you will likely still see a green bias in the background. Use SCNR to reduce/remove it.
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#4 iwols

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Posted 08 April 2021 - 09:54 AM

thanks guys these are the master darks,master bias and rgb master flats ,does this help? all stretched

 

https://www.dropbox.....51.56.png?dl=0

 

Something is not right in your calibration which is causing the black spots. Pixels are getting clipped to zero. Possible causes would include offset being too low, offset in hour bias or dark frames being different from lights, gain being different between lights and calibration files, bias being subtracted twice. Lots of possibilities.

Second, after registration and stacking but before DBE you do want to apply the exact same crop to all your subs or DBE (especially with auto-placed samples) will not work properly.

Third is your actual question—the color imbalance. This is totally normal. Some combination of light pollution gradients and different sensitivities through different filters. There are two common approaches. The first is to use background neutralization and color calibration. The second option—even better—is to use photometric color calibration with background neutralization enabled.

After all this you will likely still see a green bias in the background. Use SCNR to reduce/remove it.


Edited by iwols, 08 April 2021 - 09:55 AM.


#5 iwols

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Posted 08 April 2021 - 10:38 AM

starting again


Edited by iwols, 08 April 2021 - 01:17 PM.


#6 iwols

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Posted 08 April 2021 - 12:58 PM

will post


Edited by iwols, 08 April 2021 - 01:17 PM.


#7 iwols

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Posted 08 April 2021 - 02:19 PM

well still going anyone fancy a try got as far as stacking/cropping just to prove my data

 

 

https://www.dropbox....y4RTH0a_ea?dl=0



#8 iwols

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Posted 08 April 2021 - 04:01 PM

well this is my best shot

Image26 finalsmall.png

 

 



#9 iwols

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Posted 08 April 2021 - 04:01 PM

well this is my best shot

Image26 finalsmall.png

 

 




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