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Red Halos around some Stars

Michael Schefter
edited July 2022 in PixInsight
Hi,

I'm rather new to PixInsight and just went through the Fasttrack videos as well as the first dozen or so WBPP videos on YouTube.  I tried using these videos as a guide to processing my own monochrome data of NGC7000.  I don't recall  changing any of the settings unless Adam did in his videos.  After running DynamicBackgroundExtraction, I ran the ChannelCombination and the LRGBCombination processes to produce a coloured image.  I did a quick HistogramTransformation and then saved it as a jpeg to produce the attached file.

What is producing the red halos around some of the stars and how would I get rid of them?  Perhaps a topic in the Fundamentals explains how to fix this?

The equipment I used was a Celestron Edge HD 11" with a Hyperstar and an SBIG8300m camera.  I used 20 second exposures.

I only had darks for this image, not bias or flats.

Thanks,

Mike

Comments

  • BlockHeadBlockHead
    Hi Mike,

    The transfer curve of LRBG Combination is something you will need to experiment with. The simplest answer is that your color data is fuzzier (stars have larger halos) than they do in the Luminance image. This could be because you sharpen the luminance or performed contrast enhancements. 

    You should make certain when you do a straight up RGB image- that the colors and stars and everything makes sense. 

    -the Blockhead
  • Michael Schefter
    Hi BlockHead,

    I did what you suggested and had a look at the LRGB Combination process.  I originally had Chrominance Noise Reduction checked.  When I unchecked it, I got the attached image.  No more halos!

    Thanks for your help!

    Mike


    NGC7000.jpg
    3334 x 2512 - 5M
  • BlockHeadBlockHead
    Ah... I see. Yes, that might do it too.
    Good job!
    -the Blockhead
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