This is only my second time capturing NGC 6357 commonly referred to the Lobster Nebula ( aka War and Peace Nebula ) First time was over 2 years ago using a OSC and Dualband which resulted in a poor image due to insufficient data and poor conditions.
This time using a bigger scope, a 2600MM with 3nm filters and significantly more data ……,
Captured over 2 nights ( 11 hours integration)
Waxing Moon 60% to 70%
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 scope
PHD2 Multistar guiding ( total error avg 0.50 to 0.60 arc sec )
Antlia 3nm Filters
Ha 60 x 5min dithered subs
Oiii 39 x 5min dithered subs
Sii 37 x 5min 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
Also processed a HOO version using one of the HOO presets with slight adjustments in saturation and colour bias
Although initial stretch was still quite noisy , the final image turned out much better than my previous attempt
Also framing was a bit out , in hindsight I should have moved the image down slightly to expose more of the upper nebulosity arm or claw . Oh well maybe next time.
Attached SHO versions ( original and rotated / cropped ) reduced IIS 200KB
Attached HOO versions ( original and rotated / cropped ) reduced IIS 200KB
Links to Astrobin below for full resolution…..,
https://www.astrobin.com/3y67e2/
https://www.astrobin.com/km14mc/
https://www.astrobin.com/5uyeqh/
https://www.astrobin.com/56ddk1/
Thanks for looking
Comments welcome
Martin