M17 Swan Nebula in SHO

[Startrek]

Here’s my latest image of M17 Swan Nebula captured over 3 nights late July ( 10 hours integration)
Waning Moon 70% to 20%
Seeing conditions average
Bortle 8 City suburban skies
8”f5 Klaus Helmerich Carbon fibre Newtonian Reflector
Skywatcher EQ6-R pro mount
ZWO 2600MM cooled to -10C , Gain 100
ZWO 7x2” EFW
ZWO EAF
Orion 60mm guide scope with helical focuser
ZWO 120MM guide camera
PHD2 Multistar guiding ( total error avg 0.50 to 0.60 arc sec )
Antlia 3nm Filters
Ha 67 x 3min dithered subs
Oiii 63 x 3min dithered subs
Sii 64 x 3min dithered subs
Darks frames from Library
Flats Ha , Oiii and Sii
Flat Darks Ha, Oiii and Sii
Analysed , Calibrated, Stacked and Aligned in ASTAP
Processed in Startools V1.8 via Compose
Colour HST / SHO preset with saturation and colour bias adjustments

Applied Startools v1.8 Spatially Variant PSF Deconvolution to de blur the image and improve fine detail. It works extremely well to tighten up fine detail but does leave the really faint stars slightly blocky due to coalescing the pixels.

Quite surprised I picked up some dark nebulosity for only 10 hours of data under B8 skies. Thumbs up to those Antlia 3nm narrowband filters, best investment I ever made to combat heavy City / suburban light pollution.

Attached Synthetic Luminance and SHO versions ( < 500Kb )

Astrobin link below for full resolution……,

https://www.astrobin.com/knglsd/

Thanks for looking
Comments welcome

Martin

[decay]

Yes, the dark nebulosity in the bright centre looks great, Martin Well done

Applied Startools v1.8 Spatially Variant PSF Deconvolution to de blur the image and improve fine detail. It works extremely well to tighten up fine detail but does leave the really faint stars slightly blocky due to coalescing the pixels.

This is a problem for me sometimes, too. I wonder if there is a way to exclude the small stars from being processed by SV-Decon? Of course that probably would not be a very kind way in terms of signal confidence, but these stars collapsing into singularities don't look pretty.

Dietmar.

[Startrek]

Hi Dietmar,
Thanks for commenting
Much appreciated
Yes SV Decon has been a topic of conversation for a few years now and I suppose if you don’t pixel peep then ringing artefacts, coalesced blocky stars and other anomalies don’t really matter so much ( the de blurring works really well but at the expense of minor annoying anomalies)
However I always pixel peep and would love some way to exclude all those faint dim stars from the algorithm. Maybe a secondary mask could be developed to exclude them. I’m currently using v1.8 , maybe v1.9 has advanced features in SV Decon to tackle that issue ?
Also SV Decon is a juggling act per image and is heavily dependent upon level of Binning, image size , signal to noise / gradient levels and resolution.
For my image scale I’ve found Binning at between 65 and 71% (which leaves me with an image size around 4200 x 2800 ) works best for SV Decon.

Clear Skies
Martin