A newly discovered comet is now faintly visible in our skies soon after sunset, if you have clear skies and a view low toward the west-southwest horizon. See our diagram from Sky & Telescope magazine, in which the yellow numbers show you the comet’s location in the evening sky for dates in October.

Comet 2023 A3 (also known, after the two observatories that discovered it, as Comet Tsuchinshan-ATLAS) is best seen with binoculars or telescopes, to reveal its faint tail. For the next few days, it will be visible close to the brightest night object, the planet Venus. The comet, like many, is falling around the Sun, and was closest to the Sun Sept. 27th and closest to Earth on Oct. 12.

A comet is a left-over from the process that formed the Sun and the planets — a small chunk of icy material with lots of dirt frozen within the ices. When the comet comes near the Sun, the heat evaporates some of the gas and frees some of the dust, which is then left behind (and pushed outward by the Sun’s wind) in a streamer called the comet tail.

Tsuchinshan, by the way, means Purple Mountain in Mandarin.  It was at the Purple Mountain Observatory in China, and the ATLAS telescope in South Africa, that the comet was first sighted.

Astronomers are not yet sure of the comet’s orbit, and are estimating its complete path around the Sun takes some 80,000 years! In which case, the last appearance was before written records were made, and the next one may see a very different Earth from the one we have today.

If you have a good camera, a long exposure photo will show you more of the tail. Or just search for the comet’s name in Google Image and you will see wonderful images from astronomical observers around the country and the world.  The second image with this post shows the comet on Oct. 3, when it was visible from South America with a long exposure that reveals more of its tail than you could ever see with your naked eye.