Photo of the Week for September 21, 2018
Throughout August and September, binocular Comet 21/P Giacobini-Zinner has been blazing a trail through Cassiopeia, Auriga and Gemini. The comet’s journey has brought it near several bright open clusters, but the most dramatic encounter involved M35 in Gemini—the scene portrayed in the photo below. (The small cluster next to M35 is NGC2158.) Raphaël Dubuc, captured the comet and clusters on the morning of September 15, from Saint-Georges-de-Windsor, Quebec. Later that night, Giacobini-Zinner’s path carried the comet directly in front of M35—a rare sight delighting observers (and imagers) across Canada. The comet remains visible, though it is fading now and will soon have to compete with morning moohlight.

Raphaël used a Sky-Watcher Equinox-80 ED 80mm f/6.3 apochromatic refractor telescope (fitted with an Orion field flattener) and Canon EOS 6D DSLR camera. The final photo combines 34 individual 90-second frames shot at ISO 1600.