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Struggling with my comet

Shawn ThompsonShawn Thompson
in PixInsight
Hello,

I'm getting this bright spot in the center of my picture. I'm getting it with and without flats. I'm shooting with a Canon R5 and Rokinon 135mm f2 at f2.4. Any ideas on what I'm doing wrong?

Thanks in advance,

Shawn
integration.jpg
8191 x 5463 - 1M

Comments

  • BlockHeadBlockHead
    Sure... comet processing is HARD. No one seems to get this! lol
    The issue is that there is a changing sky gradient in every frame. 
    So the distribution of light on top of any flat field errors will cause this issue.

    1. Flats will definitely help.
    2. Proper normalization will help
    3. Finally if the above two items are done...it is possible to remove the sky gradient.

    Can you see a difference in the results with flats?
    Some lens do have this issue...and there isn't necessarily a "fix"
    Did you normalize the data (no scale with LN)?

    I had a similar problem in my images as well. I dropped the images with the bright sky in them. It is better to have fewer high quality frames rather than a gazillion frames where the sky is too bright.

    -the Blockhead

  • Shawn ThompsonShawn Thompson
    This set I ran through wbpp so I'm guessing I didn't have no scale with LN. I just realized I ran everything from the debayered files and not the registered like I did in previous comets. I'll go through those and see if anything changes.


    The first set I did was a couple of weeks ago and didn't take flats. The gradient in the center wasn't as bad, but I had them a little underexposed. This time I had them properly exposed.
    The first set I also ran through Lightroom and saved as it's not knowing PI would take my raw files. The only thing I did was lens correction and then comet align, StarX and integration.

    Thanks,

    Shawn
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