M16 in HSS

[Benjamin]

M16 taken last night. Quite windy so couldn't continue the 8" Newt short exposure experiments so thought I'd try something else with the ED80. I have a 5nm Ha filter and, thanks to some bargain hunting, found an SII 3nm filter online. I have on order an OIII 3nm filter but after being sent the wrong one its replacement is yet to arrive. So, I'd thought I catch some data anyway and see what I could get. Ha is 59 x 2 minute subs, and SII is 29 x 2 minute subs (it got cold and late to get the matching number). While I've had fun playing with combining them in StarTools some areas remain really unclear. How far to stretch the SII data? Is some noise okay or should it really be as clean as possible even if much less visible data? The Ha and SII stacked files are attached as well as the final result - Ha as luminance and an Ha/SII/SII RGB composite loaded into each of the RGB channels. So while I had hoped to kick off with a SHO narrowband this will have to do. Comments always welcome, particularly those who use StarTools or see compelling reasons to process this differently, or just anything to do with Narrowband imaging... I know nothing...
Astrobin link: https://www.astrobin.com/full/351715/0/?nc=picks&real=&mod=

[raymo]

Its time to say goodbye Ben; off you go to the main forum. The highly
experienced members there will help you progress.
raymo

[traveller]

Excellent effort there Ben.
For my 2 cents worth, the centre is slightly over exposed, layer masking may help with that.
Also, turn the photo upside down, you have captured the eagle in full flight, so show it the right way up!
Bo

[Benjamin]

Many thanks. Appreciate the comment Ray and it’s your comments in particular that I find most grounding. The gear and time spent by the imagers ‘below’ frankly scare me! I’d be bringing a can of Emu Bitter to a wine tasting.

I was thinking the same thing about the core Bo. More to be got there for sure. As for the Eagle, I see more of a sleeping bearded bloke with an odd nose, when the image is turned 90°

[raymo]

Bo is right, of course, fixing blown out areas is one of the first discrete steps
in processing that needs to be learnt. M42 is great to practice on.
Take the plunge Ben, you'll get lots of guidance. Cometcatcher[Kevin] is
seemingly having a great time displaying his 30sec unguided multi hundred
sub images which show what can be achieved with a basic rig.
raymo

P.S. I prefer The Pillars of Creation upright, as in the famous Hubble image.
P.P.S. I hope keeping you grounded is not discouraging you.
P.P.P.S I prefer larger scale images of M16, makes the pillars more prominent.

[RickS]

Hi Ben,

Have a look at JP Metsavainio's tone mapping technique. He uses Photoshop but you can adapt his ideas to other software.

Cheers,
Rick.

[Benjamin]

Never discouraging Ray. Much better knowing the thoughts of others who have far more experience and skill, even if the photos just end up on Facebook!

Thanks Rick. I had a quick look at JP’s workflow and will have a crack at this soon. I should at least add the SII into the luminance. Removing stars seems like a bit of a challenge (I’ve been masking them out rather than removing them) but time permitting should be a fun to try in StarTools.

Q: In regards to controlling noise in an image where is this most crucial? Luminance? Everywhere?! Just how far to stretch things and balance that with the data you have. Smoother and less image or rougher and more image?

[RickS]

Hi Ben,

Removing the stars is the key for me and the only part of the process I religiously do.

If you remove stars then you can do heavy noise reduction of the NB that you're using to build the colour component. I use different settings for each and hit the noisiest most heavily.

For the luminance I usually do a noise-weighted integration of the original (with stars) NB masters and then as little noise reduction as I can get away with.

Cheers,
Rick.

[Benjamin]

Got starless Ha and SII with some slight artefacts but combined them to work on colour and ended with something a little different. I cropped the image too as the outer gaseous areas weren't really adding much (a sort of nod to a smaller image scale). Also turned it all around and got more out of the middle although this was harder than I imagined it would be. Stars need to be redone as they were just added back in via the luminance channel rather than be layered back in more deliberately. Attached are the starless images, the starless colour and the end result (for now).
https://www.astrobin.com/full/351715/B/?real=&mod=

[xelasnave]

Wow..great work Ben.
Alex

[Benjamin]

Thanks Alex. Has been fun learning new processing techniques although I still need to get more from the middle. Ended up liking a false colour version the most. Time to leave this one alone now I think 🤔