Comet Wirtanen/46P in a telescopic closeup on December 5, 2018, taken from home in Alberta. The field of view is about 3° x 2° so the comet coma is certainly half a degree across (about 45 arc minutes) and appears visually as a large diffuse glow. There’s no sign of an ion tail in this set of exposures – it might be lost amid the bright coma.
This is a stack of 4 x 4-minute exposures with the 105mm A&M apo refractor at f/6.2 guided and aligned on the stars, and a set of 4 exposures for the core aligned on the comet and masked in to add just the core with a minimum of trailing. Though even in four minutes the comet moved enough to trail noticeably at this focal length, an issue with all close approaching coments.
All with the Canon 6D MkII at ISO 1600.