Two versions of the same exposures, a "normal" color version and a negative B/W version. The latter is often used to bring out faint features in astronomical pictures.(in this case the very fait tail of the comet)
For this picture I added 5 exposures, ISO 1600 each T= 60 sec. f = 200 mm f/2.8
The exposures were made with a Canon 400D and a Tamron zoom f/2.8 (70 to 200 mm)
A small telescope was used for tracking
Date 14-1-2015 21:30