M53 / NGC 5024, globular cluster: Look: no coma!

I was too optimistic in planning M64 shot to that night. Strictly speaking the white nights have already arrived washing faint stuff away and this nonsence will last till the beginning of August. Hello Sun, Moon, planets and double stars!

 

This one is definitely not the best among the bunch of my recent shots of M globular clusters but here is a feature that I want to boast: Baader Planetarium MPCC MkIII coma corrector works!!

And it's fun to try coma corrector on the object in constellation Coma Berenices :D

 

Acquisition time (start of a session): JD2556802.389086 (25.05.2014, around 01:20:18 MSK)

Equipment:

Canon EOS 60D (unmodded) running Magic Lantern firmware override fitted with Baader Planetarium MPCC MkIII coma corrector on Celestron OMNI XLT 150 mm Newtonian riding on Skywatcher NEQ-6 Pro mount with counterweight shaft extention.

Aperture 150 mm

Focal length 750 mm

Tv = 30 seconds

Av = f/5

ISO 1600

Exposures: 66% of 60 (plus 50 dark frames plus respective master offset and master flatfield images from the library (old flatfield made without corrector works better than the "proper" one :)).

Processing: Images were converted into .DNG and fed to DSS. "Superpixel" color generation mode was used, so the final image is two times smaller than the original subs. Final touches were "creatively" done in Photoshop. I have tried to protocol the processing in order to adhere to it next time, so in gereral it looks like:

1) setting gamma to 2,75;

2) setting black level rougly 8-10 8-bit units below actual minimum;

3) applying higly assimmetric sigma-like curve (that's "creative" :);

4) fine-tuning the background to 1-2 8-bit units;

5) setting gamma to 1,2.

Done