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Any planned followup to the Fabian Neyer Star Removal videos?

Wade Hilmo
in PixInsight
Hello,

Are there any planned followups to the Fabian Neyer Star Removal videos in Horizons?

The method described does a good job of removing stars that follow a normal brightness distribution.  But it does not remove significant diffraction effects from very bright stars.  You can see this in the M27 image in the existing videos, where there are a handful of residual halos and spikes from the very brightest stars.

My interest isn't necessarily in diffraction spikes specifically.  In my case, I am using an ASI1600MM-cool camera with a Panasonic sensor.  The cover glass on the sensor does not have an anti-reflection coating, and there is a very distracting reflection artifact around very bright stars.  Since it's real signal from light hitting the sensor, just like diffraction spikes, I'm making an assumption that techniques to remove diffraction spikes would be a good place to start.

In some cases, where there the star is colored, the effect may show up in one channel, but not another.  The current project that I'm looking at is an HaOIIIRGB image of the Bubble Nebula.  The star in question is SAO 20562, which is quite blue.  The artifacts show up clearly in the OIII data, but not in similarly stretched Ha data.  It's also present in the RGB masters.

My intention for the data is to do a bicolor of the narrow band data and use RGB color for the stars.  I like the stars in the Ha master, and would like to remove the stars from the OIII prior to doing the bicolor blending, and than take only hue data from the RGB and apply it to the stars.

If you have any suggestion on how to approach removing complicated stellar artifacts, I would be interested in hearing about it.  I would also be happy to make the calibrated and integrated masters available, if you would like to take a look, or even use them for a tutorial.

Thanks,
-Wade

Comments

  • Wade Hilmo
    Just as an additional note, I uploaded a crop of the star in question above from the RGB.  It shows the reflection artifact that I am describing.


  • BlockHeadBlockHead
    Wade,

    My intent was to show Fabian's technique- but ultimately its application is a skill to master. No one had produced (or reproduced) the steps he demonstrated in his talks. This is what I did in the video- and showed the results to the best of my limited abilities to reproduce his work. My tutorial was my attempt of demonstrating to the audience of possible customers that I can indeed explain stuff... this is obviously a powerful technique- indeed I used elements of it to create the star de-emphasis technique I made.

    By the way, the take away of the technique isn't entirely the removal of stars. There are many methods that do this in different ways. Fabian's technique has a scientific bend since it can be used to minimize scattered star light (and see other nebulous structures).

    Perhaps someday I will revisit this- but at the moment it isn't a high priority for me. 

    -the Blockhead
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