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RGB PCC washed out

Alan Karty
in PixInsight
Hello Adam.  It's been a while, but I made time to come back and do pretty work.

I am following your M51 tutorial with NGC2835.  My issue (and I have encountered it before) is that my RGB after PCC is so dreary compared to your RGB after PCC.  My RGBs don't come out colorful. Can you advise?

Is a linear JPEG useful?  The XISF is 115K.

Thank you.

Alan

Comments

  • BlockHeadBlockHead
    I think just attach a screenshot of what you mean..this would be helpful.
    Most people that write what you do are using an OSC sensor.Are you?

    Also, you should be using SPCC (PCC is the old thing... very old).

    -the Blockhead
  • Alan Karty
    Did SPCC with Ideal QE curve and Astrodon filters.  What a difference.  Graphs were tight. Thank you.
  • Alan Karty
    Spoke too soon.  See attached SPCC screenshot.  The purple band at the top did not appear in the attached DBE screenshot.
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  • BlockHeadBlockHead
    Sorry, I do not understand... The purple band is in both images. 
    The images are just two different stretches it appears to me.
    Is this the TelescopeLive data you are using? 

    You know I have a tutorial on this very galaxy and data set right?
    It is one of my oldest ones.... 

    -the Blockhead

  • Alan Karty
    I want to understand what the purple band is.  This is Telescope live data.  I want to process this object using the latest techniques elaborated in your M51 tutorial.

    I reviewed my DBE.  No purple band in the original RGB.  Purple band after DBE.  Rest of DBE image is smooth.  Background model is solid red!

    Attached before and after DBE screenshots with Autoboost and rgb background.


    Screenshot 2024-08-20 113931.png
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    Screenshot 2024-08-20 114042.png
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    Screenshot 2024-08-20 114114.png
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  • BlockHeadBlockHead
    A couple of things...

    1. There is a band in the original RGB (though a different color). When DBE does its job- it will attempt to correct it. However, the band is a "small" spatial feature that requires special treatment in terms of sample placement/density/settings.
    2. If you generated samples (instead of placing them) and you allowed the samples to lie on the dirty edge you will have the result you show. This is a no-no for DBE. 

    -the Blockhead
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