My first clear new moon period so far this year so took the opportunity to image one of my favourite broadband targets , M20 Trifid Nebula, under City Suburban Bortle 8 light polluted skies. Imaged over 4 nights with poor to average seeing conditions.
Due to heavy light pollution I opted for short subs ( 30 sec )
I also captured Ha data as well to create my first Ha LRGB image.
8 hrs LRGB total integration
2 hrs Ha data
8”f5 Klaus Helmerich Carbon fibre Newtonian Reflector
Skywatcher EQ6-R pro mount
ZWO 2600MM cooled to -10C , Gain 0 LRGB , Gain 100 Ha
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 LRGB Filters and Ha 3nm filter
Lum 450 x 30 sec subs
Red 190 x 30 sec subs
Green 180 x 30 sec subs
Blue 180 x 30 sec subs
Dithered every 3rd Sub
Ha 42 x 180 sec dithered subs
Darks frames from Library
Flats LRGB and Ha
Flat Darks LRGB and Ha
Analysed , Calibrated, Stacked and Aligned in ASTAP
Processed in Startools V1.8 via Compose L + Synthetic L RGB , RGB.
Created both an LRGB image and a LRGB with Ha Accent or Ha LRGB image.
Under my heavy light polluted skies imaging broadband targets during the new moon period has been almost a waist of time due to the any usable signal being swamped with noise ( gradients). When the moon is up it’s a definite waist of time.
However this time I used really short 30 sec subs at Gain 0 on the 2600MM and for 8 to 10 hrs of data the initial Auto stretch was remarkably clean with some excellent detail. Gives me confidence in the future now during new moon periods.
The downside is that I had to capture over 1000 subs with sub file sizes of 51MB.
My Lappy, stacking software ASTAP and post processing software Startools did and excellent job of handling the data load.
Links to Astrobin below for full resolution…….,
https://www.astrobin.com/rde4nn/
https://www.astrobin.com/j05tfu/
Attached original frame versions , Crop frame and Super Crop versions in LRGB and Ha LRGB ( IIS 200Kb limits )
Thanks for looking
Comments welcome
Martin