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"gradient" from L-extreme filter

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#1 dijonpepperberry

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Posted 24 July 2021 - 09:36 PM

Hi everyone - trying to diagnose something real quick!  I can generally make up for a lot of this in post processing but I wanted to check my understanding.

 

Setup:

  • Tak 85FSQ-EDX
  • EQ6-R-Pro
  • ZWO Filter Holder
  • QHY 268C
  • L-Extreme Dual Pass Filter

The issue:

When I capture using the filter, there is a *color* gradient from the filter itself. Is this because of sensor tilt?  the filter should be one color but its always pink on the left green middle red left. no matter the orientation/position of the scope. It makes my ABE/DBE very finkcy if i don't really really select my samples carefully i get some seriously neoned stuff.

 

I'm assuming a good set of nightly flats and all that should help, but is this something I can avoid from some kind of tilt-fixing?

 

I attached a quick stretched sub of the veil nebula from last night. the red-to-green-gradient is pretty clear. I don't see this for other people shooting with this filter in the tutorials i've watched.

 

Thanks for any advice!  I'm still learning but I'm having a blast! clear skies everyone.

 

 

 

 

 

 



#2 dijonpepperberry

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Posted 24 July 2021 - 09:40 PM

Sorry that upload didn't work

 

wwBvfiy.jpg



#3 Bretw01

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Posted 25 July 2021 - 12:23 PM

Looks like vignetting. Can you rotate the camera and not the scope? If so you will probably see the same thing. I think you will be fine with properly calibrated flats. Should turn out to be a nice image!


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#4 F.Meiresonne

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Posted 25 July 2021 - 01:11 PM

Imho, looks like vignetting wich should be solved by flats and bias .



#5 jonnybravo0311

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Posted 25 July 2021 - 01:53 PM

Tilt would present itself as one side/corner of your image would have elongated stars. What you're getting here is normal vignetting associated with uncalibrated lights. Take and apply the flats/darks/biases and that issue will disappear.



#6 dijonpepperberry

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Posted 25 July 2021 - 01:58 PM

Looks like vignetting. Can you rotate the camera and not the scope? If so you will probably see the same thing. I think you will be fine with properly calibrated flats. Should turn out to be a nice image!

 

Imho, looks like vignetting wich should be solved by flats and bias .

 

Tilt would present itself as one side/corner of your image would have elongated stars. What you're getting here is normal vignetting associated with uncalibrated lights. Take and apply the flats/darks/biases and that issue will disappear.

 

Thank you all!  Yes rotating it produces a similar image so that's really good news. I did about 70flats + 70darfklats with the filter using NINA flats wizard and it seemed to work really well.  thank you everyone!  I look forward to this one!  4.5 hours so far, aiming for about 12 or so!


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