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View Full Version here: : PixInsight: Blending Ha with RGB / Using Ha in L


AstroTanja
25-05-2014, 05:42 AM
Recently I did LRGB and HA of the Gabriela Mistral Nebula, since then I have edited the HA data acquired:
View here: http://www.astrobin.com/93467/
Original LRGB edit: http://www.astrobin.com/92853/

I am attempting numerous ways to do a HA and RGB combination. I've tried the NBRGBcombination script, which produced nice results, but the overwhelming red makes it a little difficult to saturate/edit the other colours without it looking too saturated in general.
I've played with various %'s of mixing the HA in with red, but would appreciate if someone has more pointers or tutorials I could work through.

But what I would really like is to use the HA as Lum. It improves the detail tremendously, but leaves the entire image looking too “salmon” coloured. Is it common to use HA in Lum?

Here is HA blended into the Red channel, as well as 80% blended into Lum:
http://www.astrotanja.com/wp-content/uploads/2014/05/NBRGB_plus_80HA20Lum.jpg
I've not edited it much further than the new LRGBcombination as my blue stars do not look right

I've tried various things, like removing stars from the HA to blend with the Lum, or use the HA straightforward instead of Lum – but nothing seems quite right. It also seems to cause problems with my mid sized blue stars, that have more of a blue glow around them when using HA in Lum. (I've tried a MT on the Blue channel before combining but it made no real difference)

Or I could possibly have been staring at the screen for too long. I don't know what looks right anymore. I know there is possibly no absolute right or wrong way, but would appreciate if someone had any insight or advice on what I should try. :-\

Thanks!

Andy01
25-05-2014, 08:09 AM
Nice shot Tanja, lots of good detail there.
Regarding HaRGB blending- Have you seen this tutorial?
http://starizona.com/acb/ccd/software/ps_hargb.aspx????
Cheers
Andy

AstroTanja
25-05-2014, 09:15 PM
Thanks for this.
I'll work through it - and although I want to stick with PI on this, processes should be the same. If I can get it looking right in PhotoShop I can apply the same principle to PI.

allan gould
26-05-2014, 12:22 AM
Nice image Tanja. I'm never happy with my colour images and find the more I play with processing the worse it gets, but yours looks fine to me.
Allan

DavidNg
26-05-2014, 11:32 AM
There is a good technical explanation on the art of blending Ha and RGB by Vicent Paris at PI website. It appears they are developing a new approach on blending Ha and RGB. Hope it will be released soon. Definitely an issue that concerns many of us which gratefully addressed by the PI team.

Cheers David

Link is here: http://pixinsight.com/tutorials/narrowband/index.html

troypiggo
26-05-2014, 07:15 PM
David, I've read that article and tried to follow it through using PI. Never been successful. Have you tried using that method for real (ie your own) images? If you have and were able to follow the process to the end, I'd love to have a chat with you.

There have been many questions on the PI forum asked about it, and I don't think I've ever seen conclusive answers. Typical response from people is just to use the HaRGBCombination script (think it's call NRGBCombination now). But that script does not use the Vicent method. I've even PM'd Vicent and Juan directly and no response.

AstroTanja
27-05-2014, 04:10 AM
Thank you for the feedback.
I posted the same question on the PI forum and Juan Conejero replied with the same link.
I will try make some headway, and post results back here.
If I manage to get something looking half decent I'll document my steps. They say that its an easily automated algorithm so that might be coming soon to a PI update.

DavidNg
27-05-2014, 04:28 PM
Hi Troy, as Tanja has mentioned the blending script is not out yet. I've also tried various combination with Ha and R percentages, regardless of any figures the outcome always disappointed, pinkish salmon nebulae and odd star colors. Hope PI will release the script soon. Regards David