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Spookyer
06-09-2015, 07:36 PM
I got some reasonable HA and RGB data on SL17 the Wolf nebula while at astrofest.

I have spent 4 hours today with Pixinsight and basically got nowhere with it. I think what I need to do is use the Ha data to get a red emission nebula look and then make the Ha stars look small but normal using the RGB data. My inspiration is the image Paul Haese did a while back.
http://www.iceinspace.com.au/forum/showthread.php?t=109296&highlight=sl17
I don't expect mine to achieve that standard but that is what I was aiming for.

I can't find a tute anywhere to help me. The combinations I do all end up with a heap of stars and not sufficient nebula to properly define the dark nebula that is the wolf, even though there is strong Ha data there.

Any tips on the order of the processes I should be using to get that effect?

Cheers
Brett

RobF
06-09-2015, 09:11 PM
You may not wish to Brett, but one option is to put the master FITS data up somewhere for people to try and work on.

Can be really frustrating when you've spent lots of time and don't feel your getting a decent image. My 2cents on workflow I'd attempt initially:

Create synthetic lum
Balance RGB and flatten/colour balance/stretch as possible

See if lum has enough data to survive deconv or other contrast enhancement/tightening. Probably need masking of stars and neb which is half the battle. Possibly add some Ha to Lum.

Consider adding 50% Ha to R
15% Ha to B
Attempt new RGB with modified R and B.

LRGB combine
Final color, saturation, contrast tweaks.


From what you've said, my generic approach for brighter nebs/galaxies may not be best for a faint dark neb. May even require separate star and neb processing.

LewisM
06-09-2015, 09:35 PM
Please post the individual FITS - would love to have a crack.

If you like what you see, people will let you know how they got there.

Paul Haese
09-09-2015, 09:26 PM
From memory I blended Ha to Lum at 28% and Ha to red 26%.