Comet Tsuchinshan-ATLAS vaults into the evening sky on or about Oct. 11th. Map dates are shown for 0h Universal Time (UT) and latitude 40° north. For example, Oct. 12th at 0h UT becomes Oct. 11th at 8 p.m. EDT. C/2023 A3 will begin its evening run around magnitude –2 and display a long, westward-pointing tail. The comet quickly climbs away from the Sun into a dark sky, while steadily fading. On Oct. 14th UT, it will shine at around 0 magnitude; on Oct. 17th, 2.5 magnitude, and magnitude 4 on Oct. 22nd.
Sky & Telescope graphics