Adding Ha to LRGB

Questions and answers about processing in StarTools and how to accomplish certain tasks.
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Rkonrad
Posts: 247
Joined: Sun Feb 07, 2016 2:55 am

Adding Ha to LRGB

Post by Rkonrad »

I think this topic has been mentioned before but I don't recall a solution - sorry if I missed it. I have seen so many amazing images of halrgb online but I have never been successful in my processing. This is what I have tried:
1. I have mixed (at the linear level) Ha with L in a variety of percentages ie 50/50, 30/70, etc then added the rgb to compose.
2. I have also mixed Ha with R and combined that with the Ha /L.
3. My latest attempt was to "add" in layers the Ha overtop of L. I did the same with Ha and R but in the end the processing didn't look any different than the lrgb.

I have seen great images and I believe Pixinsight has some good workflows on this. I'd love to hear a response and if you have an example, I'd love to see it.

Thanks Richard
Rkonrad
Posts: 247
Joined: Sun Feb 07, 2016 2:55 am

Re: Adding Ha to LRGB

Post by Rkonrad »

I just realized there is a NBaccents slot in compose for me to insert my ha data. I will try it!

Richard
Rkonrad
Posts: 247
Joined: Sun Feb 07, 2016 2:55 am

Re: Adding Ha to LRGB

Post by Rkonrad »

The new feature is excellent! Here a link to a lrgb version of my target https://www.flickr.com/gp/rkonrad/41sdp0 and Halrg with nbaccent https://www.flickr.com/gp/rkonrad/633vL1. These are not my final versions as I have more work to do.

Richard
Mike in Rancho
Posts: 1141
Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: Adding Ha to LRGB

Post by Mike in Rancho »

Nice images, Richard! :D

This topic has been discussed quite a bit even recently, and I was going to mention the NBA option but you found it yourself. :thumbsup:

I've only used it a couple times so far myself, and there are a lot of controls and settings to play with between the two screens. It's also quite handy that you can variably control both luminance and color contribution.

Ivo will provide the best take on the issue of course, but I think the general summary of the discussions usually boils down to -- what is the intent of the channel combination, and does it make actual sense to do so. It can be quite target dependent as to how the image reacts, and probably even across a single image for different parts of it. But even with the power of NBA, a lot of the same concerns still apply - which is that altering the underlying luminance of an image not only changes what structures are visible, but can affect the final coloring as well, possibly washing those colors out.

I like both the rho2 and rho7 you linked, though you noted that neither was finalized. Possibly a middle ground would do, that boosts some of the surrounding Ha but also maintains more of the dark nebula backlit by the very dense starfield? I do like the stars in version 7, though something may have gone amiss with the glob?

Good stuff.
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