Comet Wirtanen

A photo composite of multiple exposures. As seen on Astronomy Picture of the Day, Comet 46P Wirtanen hangs in this starry sky over the bell tower of a Romanesque church. In the constructed vertical panorama, a series of digital exposures capture its greenish coma on 2018 December 3 from Sant Llorenc de la Muga, Girona, Catalonia, Spain. On December 16 it was at closest to Earth, passing at a distance of about 11.6 million kilometers or 39 light-seconds. That’s close for a comet, a mere 30 times the Earth-Moon distance. A good binocular target for comet watchers, Wirtanen was visible to the unaided eye from a dark sky site.