Flaming Star Nebula C31/IC405 - can't decide between two colour choices

[ramdom]

Hi all, it has been a while since I posted here. I used to post my Lodestar X2 images regularly but I've started getting into full on AP (in fact, this below is my second "real" AP image that didn't involve live stacking, and my sixth high resolution one) with a QHY163M camera and a bunch of refractors for different FOVs. I've been meaning to post my images here but it's only now after starting to use PI that I've gotten comfortable with my technique (not even close to being that great at PI yet but definitely getting the hang of it). I always struggle with colour choices. In this particular target, for which I posted the mono Ha image in the imaging challenge, I got a small amount of O2 signal (after two hours) but I did get a decent amount of S2 signal. What I found is that the S2 signal overlaps a lot with the Ha signal so trying to distinguish it using the blue/gold tones of traditional Hubble Palette (which is something I've only learnt to do as you can see from my Astrobin page here: http://www.astrobin.com/users/ramdom/) proved to be difficult so I decided to go with shades of one colour. In the first image (uncropped - you can see the framing not lining up perfectly at the left), I did manage to push the S2 signal more towards white and grey/magenta (it's there if you look closely).  In the second image, the darker blue indicates Ha only signal and lighter blue indicates overlap with S2 signal. My question is which of these two images you prefer (or the mono version, posted separately here and current on my Astrobin page).  I'd appreciate any comments and criticisms and I'm glad to be back on here again!

--Ram

Flaming Star nebula C31/IC405/Sh2-279 (c-sho). 

Total integration: 540 minutes/9 hours (42 x 5m for S2/red + 42 x 5m for Ha/green + 24 x 5m for O3/blue).
Camera: QHY163M (16mp mono) CMOS cooled to -20 degrees C.
Telescope: Stellarvue SV70T triplet apochromat refractor @ f/4.8
Mount: Paramount MyT.
Filters: Astrodon 5nm Ha, 3nm O3, 3nm S2.
Software: Sharpcap, PixInsight, Nebulosity, Photoshop CC.

 

 

[carastro]

They are both nice, but the first one grabs me the most.  Bluer and seems to show more nebulosity.

Carole 

[michael.h.f.wilkinson]

Both are unusual choices, but I do like them. The first does bring out more detail, I feel

[ramdom]

Hi Carole, Michael, thanks for your comments! 

Michael, I agree it's unusual and normally when that occurs it is by design but this time I didn't have seem to have much of a choice.  Generally I am able to convert a greenish SHO image produced to the golden blue of the Hubble palette images using a web-based guide in Photoshop CC. But this time when I do a PhotometricColourCalibration in PixInsight I get a completely green image similar to the blue images above and when I do just a ColourCalibration I do get the yellow core but one of the first steps in converting a greenish SHO image initially generated to a golden blue image involves converting the green to yellow, so everything ends up being the same colour anyway.  I've tried to change the yellow first to a blue or a gold but it renders the image flat.  Maybe the problem is doing it in Photoshop and I should try to do it in PI using masks but I still need to learn a bit about that. 

The other option is the HOS scheme which results in a red Flaming Star but I decided to go with a blue flame instead. I attach both the HOS image as well as the SHO image with ColourCalibration applied (which highlights the yellow more, unlike the PCC which makes it all green). As you can see in the HOS scheme, the darker (purer) red signifies the Ha contribution and the lighter red/magenta signifies the S2 contribution.  There is a bit of O2 signal in there as well. 

--Ram