I recently captured the Helix planetary nebula during a rare run of clear nights under my City suburban B8 Skies during the New Moon period with mixed results.
Acquired the following data over 5 nights -
160 x Ha 3 min dithered subs
152 x Oiii 3 min dithered subs
106 x Sii 3 min dithered subs
Total integration approx 21 hours
Full calibration suit -
Darks
Flats
Flat Darks
8” f5 Klaus Helmerich Carbon Newt
Skywatcher EQ6-R pro mount
Imaging camera ZWO2600MM , cooled to -10C , Gain 100
PHD2 Multistar guiding ( 0.45 to 0.60 arc sec )
Tracking and Goto EQMOD and Ascom Stellarium
Captured with APT
Analysed , calibrated ,stacked and aligned in ASTAP
Post processed in Startools V1.8
The end result was a bit disappointing considering the amount of data acquired as I expected to expose more outer detail which ended up being just noise.
Faint objects like the Helix definitely require substantially more data to resolve fine detail under heavy light polluted B8 skies.
I decided to capture Sii data which is extremely faint but ended up just stacking noise which didn’t help.
In hindsight I should have captured significantly more Oiii data as this filters signal is severely compromised with noise under B8 , 10 times worse if the Moon is up.
Also conditions were average with poor seeing from 8pm to 10pm on each night.
Anyway processing was very conservative as I didn’t want to expose the background noise , gradients and undulations etc.. so background does appear clipped but it’s not as Startools won’t allow the blackpoint to be 0.
Astrobin link below for full resolution……,
https://www.astrobin.com/su9nt3/
Attached original frame size version and crop version in IIS 200KB
Thanks for looking
Comments welcome
Martin