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First Hubble Palette Image - Skull Nebula

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#1 dcm_guitar

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Posted 01 March 2021 - 11:25 PM

This is my first Hubble palette image.  I've just started monochrome imaging.  I collected the data over Feb 27 & Feb 28 under nearly full moon conditions in Bortle 6.  The images are:

 

SII: 10x180sec & 10x300sec

Ha:  10x180sec & 10x300sec

OIII: 10x180sec & 10x300sec

 

I processed in Pixinsight using a mixture of the Light Vortex tutorial and some of my own choices.

 

https://astrob.in/krgxwo/0/


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#2 Stelios

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Posted 02 March 2021 - 03:34 AM

I like it. It's different. Good detail. Much lighter than the typical Hubble palette, which I also have a lot of trouble realizing. 

 

Have the stars been removed and replaced? There's some artifact on most stars, visible when you go to full size. 



#3 Serial

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Posted 02 March 2021 - 05:22 AM

Seems to me you need to get out of the beginners forum! Beautiful!

#4 imtl

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Posted 02 March 2021 - 06:32 AM

Very nice color scheme. Not typical HSO pallete. Very gentle. I think that maybe the artifacts in the stars are from masks not working properly. But you reall need to zoom in to see that. 

 

Regardless of that, I think you have tilt issues. The upper part of the image is a bit defocused compared with the lower part.



#5 jonnybravo0311

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Posted 02 March 2021 - 10:15 AM

I like the atypical color scheme you used. My very nitpicky comments echo what have already been written... when completely blown up and viewed in full resolution, there are artifacts around the stars. Deconvolution maybe? Maybe masking just a bit off? Looks like a bit of tilt as the upper left is a bit out of whack. Finally, I would have framed it a little differently.

 

That's all for my nitpicking... I think the image is very nice overall. You did a great job with it!



#6 dcm_guitar

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Posted 02 March 2021 - 01:56 PM

Thanks for all the feedback!!!

 

The stars are off definitely off a little, and I'm sure it's user error.  The first time I channel combined and then adjusted the colors (green correction) the stars were all VERY magenta.  I know this is expected, but I decided to try a slightly different approach to see if I could eliminate the magenta stars without having to create without having to result to masks and deconvolution and getting the halos corrected (I'm still new to Pixinsight).  Here's what I tried:

 

  1. Register the three channel stacks with each other.  I used the Ha stack as the reference
  2. Once registered, run StarNet on each image band to remove the stars and end up with six images:  three nebula only (SII, Ha, OII) and three star masks (also SII, Ha, OIII)
  3. Channel combine the star masks.  Then, desaturate the resulting RGB image using the curves tool.
  4. Channel combine the nebula images and "play" with the resulting Hubble palette color scheme.
  5. Combine the desaturated star mask with the Hubble palette nebula using Pixelmath

I'm not sure what I did wrong, but I also noticed the alignment with the stars seemed off, and I'm pretty sure it's the OIII star mask that's the cause of the issue.  Maybe I didn't use the registered file?  I'm not sure.  Because I had never done a Hubble palette before, I "went with it" to get a final result.  The result turned out better than I expected even with a mistake.

 

I think my tilt issues are more likely user issues with registering views instead of files.  My Pixinsight "desktop" was messy and it's possible I closed the wrong view for my OII stack.  *shrug

 

I'll likely play with this data a lot more and try different processes to come up with a Hubble palette result that I like.  I tried not to go "over the top" woth the colors on my first pass.  The next time through I might go nuts and see what happens.

 

Again, thanks for the feedback!!!!!




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