Comet C/2023 A3 — known simply as Comet A3 — was first discovered last year and was first visible in the night sky earlier this month, with peak viewing from Oct. 16 through Oct. 20. The comet is projected to swing through our solar system again sometime between 80,000 years from now and never.

Comet C/2023 A3 will be visible in the sky over the next few days for more than an hour shortly after sunset each night. For those in Pennsylvania, the sun sets around 6:25 p.m., so the best viewing starts around 7:10 p.m. The comet will be visible for about 90 minutes before it dips too low.

Comet C/2023 (Tsuchinshan-ATLAS) is putting on a once-in-a-lifetime show. Here's how to see it before it leaves.