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Processing stars separately from Nebula

Mark Earhard
edited March 8 in PixInsight
Hey there all-

I'm trying to process some
data from the Eagle Nebula, and I'm trying to "fix" my stars.  I've used
SXT to separate the stars from the nebula, so I could work on them
separately.  I used BXT to reduce the halos and round up the stars, but
I'm getting these artifacts around the bright stars and I'd like to
reduce them:

attached is a screen grab of the original, and the BXT version.  I kinda went ham with BXT trying to reduce the halos, which worked reasonably well, but there's still a little left.  I haven't done much processing to the rgb image pre-star removal, just DBE, so I'm pretty sure I'm not seeing an artifact from another process.  I tried to keep it pure.

Is there a process that will help eliminate the rainbow spikes, and does anyone know from whence they came?  My scope is an ETX-125 Maksutov Cassegrain, filters are astronomik deep sky, and the camera is an asi2600mm.

Wow uploading was taking forever.  Let's try this:


Comments

  • Mark Earhard
    edited March 8

  • BlockHeadBlockHead
    BXT is only going to enhance artifacts like those. BXT can fix aberrations that are the sort that lenses/mirrors produce. These artifacts are something else. I do not know if they are a wee bit of microlensing or some other diffraction effect (more likely) of something in your optical system. The star quality isn't great in your data. The better the quality, the easier it becomes to diagnose.

    There is no easy answer to get rid of the spikes other than wholesale replace your stars with artificial ones or cosmetically affected (strongly) ones.

    Sometimes you have to choose where to devote your energy. Are you certain this is a processing solution you want instead of running this down as a equipment/acquisition issue?

    -the Blockhead

    -the Blockhead
  • Mark Earhard
    I'm fine with it being an acquisition issue, I was just hoping to find a way to get rid of them.

    I had only like 40 frames of r, g, b, and L at 300s total for this object, I was at a friend's ranch for a brief time and I had to pick my battles.  The data for this object was not nearly as good as it was for some other objects I'm processing from that trip.

    I wonder if it could be collimation of my scope.  I'll have to look at my other images from that trip and see if the same thing appears.  Since they're "rainbow" I'm guessing it happens across all filters, and thus the problem is either collimation or some other flex in the scope.
  • BlockHeadBlockHead
    According to this page:

    There are microlenses. I believe this is the answer. Bright stars will show the effect. 
    I do not think they are easily removed. Being collimated will make the effect symmetric.

    I avoid sensors will micro lenses. The old SBIG ST10XME had them.

    -the Blockhead
  • Mark Earhard
    Ah thank you Adam.  :)  The more you know.  At least I know what the problem is.  I'll collimate at least, that might get rid of the spikyness and make the data a bit easier to process.
  • Mark Earhard
    As much as I hated to do it, I sharpened the stars with BXT and then clone stamped my way to victory.
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