This is Comet Tsuchinshan-ATLAS, C/2023 A3, in wide-angle nightscape scene over the Badlands of Dinosaur Provincial Park, Alberta, on October 23, 2024.

Dinosaur Park is home to one of the world's largest repositories of late-Cretaceous age fossils, from the time just below the K-Pg boundary layer created by the massive impact of a comet or asteroid that brought the age of non-avian dinosaurs to an end.

The Moon was well out of the way this week, so the comet was in a dark sky and higher than the previous week. And it was moving slowly each night up toward the rich summer Milky Way at left. The comet was easily visible to the unaided eye in a dark sky like this, so was about magnitude 4.5. The tail was visible to the eye, not just the bright coma, so it looked like a comet in the sky, not just a fuzzy star. In binoculars, the tail stretched across the 7º field, similar to the extent recorded here. The comet was in Ophiuchus at this time.

A faint anti-tail was still visible in front of the comet, though it is more diffuse than a week earlier when it appeared as a sharp spike.

Bands of green and red airglow tint the sky, as well as skyglow from the lights of Brooks to the southwest. We had our first snow just two days earlier.

The Milky Way contains the rich collection of star clusters, nebulas, and star clouds that populate this area of sky toward the galactic core. The bright Small Sagittarius Starcloud (aka M24) and, above it, the Scutum Starcloud stand out.

This image with a 28mm wide-angle lens has a field of view of 65º by 46º. The latitude was 51º N.

Technical:
This is a blend of tracked images for the sky and untracked images for the ground:
- A stack of 5 x 1-minute tracked exposures at f/2 and ISO 1600 for the sky, followed immediately by...
- A stack of 2 x 6-minute untracked exposures at f/2.8 and ISO 800 for the ground.
All with the Canon R5 and RF28-70mm lens, on the MSM Nomad tracker, and with an URTH Night light pollution reduction filt