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Well, that's a trick I'll use again: A soupcon of RGB for my NB

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#1 fewayne

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Posted 29 November 2020 - 01:18 AM

I'm working on the Pac-Man Nebula in Ha and OIII, and the first night's data taught me a little more about using Astro Pixel Processor's Combine RGB tool. Well, the data and Sara Wager taught me, at least. Getting the color I wanted in the nebula wrought all manner of havoc upon the stars. And to be fair, the best I could have hoped for from bicolor narrowband data would be...white dots.

 

But intrigued by a couple of by-the-way comments from Wager and from AstroStace, on a whim I tossed 10x30" each RGB onto the front end of tonight's imaging. Figured the moon was up and I'm imaging from my Bortle 8 back yard anyway, so I wasn't going to try too hard.

 

I had to work the light-pollution/gradient removal tool pretty hard to get there, but I wound up with some nice, quite colorful stars, calibrated along the H-R line so the colors will be reasonably accurate. Instead of doing starnet++ star removal and then subtracting that from the original to get a stars layer to be blended in later, I can just work with the starless image and combine it with the color-stars one at the end.

 

There's a bunch of noise in the background, of course, but I don't even care -- since all I want from this layer are the stars, I can clip the background right to black and let the nice 7.5 hours of narrowband data supply it.

 

Of course this is a very well-known technique, but I had no idea that one could get so much out of so little integration time and effort.


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#2 imtl

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Posted 29 November 2020 - 01:31 AM

What I did just the other day. I grabbed 20 minutes on each RGB (probably too much for this). RGB combine. PCC. and stretched. I then saturated the RGB image a lot.

 

After finishing up my NB image, I got a star mask from it using starnet++. Convolved it with 1.2pixel std and then put that as a mask on the NB image, and dumped the RGB stars on to that. Just the tone map. I kept the NB stars resolution since they are always tighter than RGB.

 

Worked very well for me.



#3 fewayne

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Posted 30 November 2020 - 11:55 AM

Got it done. At least for now. I may go back and redo it without all the starnet artifacts, but I managed to Healing-Brush away the most egregious ones. Looks as if someone fired a 12-gauge loaded with rock salt at the nebula if you pixel-peep.

 

https://www.astrobin.com/wtceos




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