Total Re Process M17 Omega (Swan) Nebula

[Startrek]

As my last posted image of M17 was a complete noise fest and I have no idea why I posted it , decided to totally review subs , re stack and reprocess the data set and post a more realistic rendition of this wonderful celestial object to do it justice.

Review subs in ASTAP again ( discarded 5 subs )

Re Register and re Stack in DSS with following setting changes
Check No white balance processing
Select per Channel Background Calibration for Light frames
Select Align RGB Channels in final stacked image

Reprocess in Startools
Set a Specific ROI in AutoDev around the object and ignore fine detail 2.5 pixels (Resultant stretched image removed residual gradient whilst maintaining dynamic range and fine detail in and around main structure )
Used a Basic Wipe ( in lieu of Narrowband Wipe ) with dark anomalies set at 4 pixels due to higher than expected LP gradient
Used HDR Optimise soft
Used Sharpening Dark only
Decon set at 1.5 pixels
Shrink module , tighten stars by 5 pixels
Super Structure module used Dim Small feature
Colour module used Scientific ( colour constancy )
Final noise reduction 4 pixels

A couple of OSC bicolour renditions

Thanks for looking
Comments welcome

[PKay]

I think you have done it justice M.

Like the first one best, but they're all good.

To avoid the 'noise fest' I use an absolute minimum of 30 subs
(in my case each filter) and like you, carefully check each one before stacking.

Nice processing :thumbsup:

[Startrek]

Thanks PK
Appreciate it
You haven’t imaged unless you’ve imaged under Bortle 8 with neighbours flood lights blasting your yard
If these narrowband filters weren’t invented for emission nebula, I probably wouldn’t image that much in Sydney to be perfectly honest.
When in Sydney my subs have a heavy green cast when viewed due to LP , down south the subs are almost black and white, it’s chalk and cheese.
I admit 3 or 4 more hours on this Nebula would help a great deal but like most folk you want to move onto other targets as clear nights have been few and far between over the past 9 months and it doesn’t look promising in the months ahead , La Niña suppose to return in October / November
It’s certainly challenging up here
I was hoping to score some clear nights down south ( heading down tomorrow) but I probably won’t even open up the Obs as there’s rain for the next 10 days
Bummer
M.

[xelasnave]

Well worth the effort but the originals were not as bad as you suggest as I recall..
I do think reprocessing is a worthwhile pursuit as so often, as you have done , you drop some subs and that can make a noticeable difference and improvement.
And processing is much like cage fighting you generally improve the more times you have a go.
Good work.
Alex

[Stephane]

Hi Martin, a really nice image image with some good colour. I look forward to trying this one day.

[Startrek]

Thanks Alex
You never stop learning in tis hobby
Keeps you on your toes
Martin

[Startrek]

Thanks Stephane
It’s a great target to image, the core is unique
Cheers
Martin