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Generate Bad Pixel Mask

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#1 Juzwuz

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Posted 13 April 2024 - 07:42 PM

https://drive.google...iew?usp=sharing

 

Is there an easy way to fix "bad" pixels in a master flat? I have dew/frost dots in my master flat and no way to re-take the flats. Luckily the lights do not have the dots. The dots appear to be very black so I thought there might be a way to generate a mask from which I can then fix them. 

 

 



#2 bignerdguy

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Posted 13 April 2024 - 10:51 PM

https://drive.google...iew?usp=sharing

 

Is there an easy way to fix "bad" pixels in a master flat? I have dew/frost dots in my master flat and no way to re-take the flats. Luckily the lights do not have the dots. The dots appear to be very black so I thought there might be a way to generate a mask from which I can then fix them. 

Those look like dust donuts and should be there.  when you process the light images with these flats it should remove the donuts from the light image and give you a smoot gradient.  This is what flats are for.  Even if they are from frost and dew are they also in your light images?  if you process the lights without the flats and then stretch the image can you see them?  if so try to process the image with the flats and see what happens.  it should  remove the circles.



#3 Juzwuz

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Posted 13 April 2024 - 11:50 PM

Those look like dust donuts and should be there.  when you process the light images with these flats it should remove the donuts from the light image and give you a smoot gradient.  This is what flats are for.  Even if they are from frost and dew are they also in your light images?  if you process the lights without the flats and then stretch the image can you see them?  if so try to process the image with the flats and see what happens.  it should  remove the circles.

The dust donuts calibrate out fine. The little dew dots are near the center of the flat and are ~1 pixel wide.

 

flat dewdots
 
flat dewdots zoom


#4 bignerdguy

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Posted 14 April 2024 - 05:28 PM

Sorry didn't see that in the image i downloaded.  I thought you were referring to the larger donuts.  I am not sure there is anything that can be done for these flats.  Someone else here will have to weight in on this.


Edited by bignerdguy, 14 April 2024 - 05:28 PM.



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