The very green Comet Wirtanen (aka 46P) appears above a snowy backyard scene – my backyard! – on December 3, 2018, as it climbs higher in the sky each night through Cetus into Eridanus in early December 2018 at this very favourable and close return. The comet was an obvious diffuse glow in any binoculars but to the camera appeared very green or cyan, as comets often do, from glowing cyanogan and diatomic carbon molecules in its coma. This is a stack of 6 x 30-second exposures with the 35mm Canon lens at f/2 and Canon 6D MkII at ISO 1600, with the camera on a Star Adventurer Mini tracker. A single exposure was blended in just for the ground to keep the bushes and foreground sharper.
Comet Wirtanen (aka 46P) as it appeared in my sky on November 28, 2018 with it still only 17° above my southern horizon, so partly in haze. The comet was obvious in big 10x70mm binoculars as a large diffuse glow. Wirtanen was moving north and had just entered my western Canadian sky the week I took this. As I write this, Wirtanen will be higher in mid-December when it is closest to the Sun and to the Earth. This is a stack of six 2-minute exposures guided on the stars, with a single exposure blended in, to provide a “core” that is not streaked from the slight motion that did occur over the 12 minutes of shooting. This was with the A&M 106mm apo refractor at f/6 and Canon 6D Mark II at ISO 3200, with the Hotech field flattener.
The periodic comet 21P, Giacobini-Zinner in Auriga on September 4, 2018 as it passed east of the triangle of stars at right called The Kids, near Capella. The comet is distinctly cyan and red. It was plainly visible in binoculars at about 7th magnitude. Some faint HII emission nebulosity, including a couple of Sharpless nebulas, permeate the field at left. This is stack of 3 x 4-minute exposures with the 77mm f/4 Borg Astrograph and filter-modified Canon 5D MkII at ISO 1600. Guided on the stars - the comet did move a little between exposures but not enough to blur its image much at this focal length. Taken from home with the field low in the northeast but on a fine night. Diffraction spikes added with AstronomyTools.
