This is Comet Hartley 2 at dawn on October 20, 2010 at its closest approach to Earth, with it about 18 million km away. This is a telephoto lens shot and shows about the same field as binoculars. Apart from the cyan colour, this view matches what the comet looked like visually with large binoculars — a round fuzzball.
This is a stack of 4 x 2.5 minute exposures at ISO 1600 with a Canon 5D MkII on a 77mm aperture Borg refractor at f/4.1 (300mm focal length). It was taken under hazy skies in the narrow window of dark time between moonset and dawn at 6:00 am on Oct. 20.