Overcompensated Vignetting

tworrall1

Member
I've had PI for a few years and still feel a newbie at processing. I've been processing out gradients and vignetting with DBE and ABE etc. I have been using only Bias and Darks during stacking. Ok time to add some new Flats I created and these showed Vignetting... I found that using a corrected master dark or loading the subs that make the corrected master dark into WBP cause the Vignetting to be over corrected ie what was dark Vignetting is now white, almost inverted. I created the Flats/Darks using this Youtube site that seems to follow the PI manual "Inside PI" The image shows clearly the effect. I have searched the net and found links to astroart that described the same symptoms , there is one error message that seems to be generated before WBP starts its run (Darks were taken with the same exposure time /temp as the lights)
Has anyone seen this effect ? or has a fix ??
 

Attachments

  • double image.png
    double image.png
    766.5 KB · Views: 71
  • corrected darks diagnostice message.png
    corrected darks diagnostice message.png
    51 KB · Views: 63
Last edited:
Tworrall,

It is likely the optimization is the problem. If you have matching darks you might try a straight subtraction instead of optimization.

Your language "using a corrected master dark" is also a potential issue. Darks are simply integrated to create a master and should not be adjusted unless you have a special case- which you did not indicate in your post.

Please consider seeing my series for additional information:


Bernd is a super hero when it comes to running down calibration issues- but I fear he will be powerless without more information.
-adam
 
Many thanks , i created master dark's using a Ipad to deliver a constant light source , in the video I watched re creating dark's etc at the image calibration stage the Bios master was used ,

Thanks for the link !

 
Many thanks , i created master dark's using a Ipad to deliver a constant light source ,

Ummm... just saying, that doesn't sound good. Did you mean you created flats using an Ipad to deliver a constant light source?
An Ipad will likely not be a good source of light for flats-but this another topic separate from the darks.
The "0" seconds is troubling as well.

I watched this person's video(s). His information is not complete. He does not show the final $%^&^! step of calibrating the images. He only shows how to make the masters. In addition- if you follow his instructions, you *DID* optimize for the Flats and perhaps (you didn't say) you did optimize when calibrating the llght frames with your "calibrated" dark? But you are not following...I think you are doing his steps and then bringing the images to WBPP. This is where the potential problem is.

You are bringing WBPP calibrated darks (which gets super confusing). This would mean you need uncheck the "Calibrate Master Dark"... which again can be confusing. I suggest you load the RAW darks in WBPP- keep the Calibrate Master Dark checked, uncheck optimize darks..load your biases and flats. Use calibrate only and let WBPP do its thing in the order you were trying to do manually.

-adam
 
Back
Top