A rare green comet will be one of two in the night sky. Here's where to look for them

Two comets are set to light up the night sky, one of which will not be seen again for over 1,000 years.

C/2025 R2 (SWAN) and C/2025 A6 (Lemmon) are expected to be visible across the country this month, weather permitting. They are predicted to make their closest approach on Tuesday evening, Oct. 21. Both comets should be visible in the western and southern skies starting about 45 minutes after sunset and continuing into the night, according to Forbes.

Lemmon, which is a rare green comet, can be seen with the naked eye on Oct. 21, according to the Royal Astronomical Society, with peak visibility near Halloween. SWAN may be visible using binoculars or a telescope, according to Starwalk, a real-time astronomical app for stargazing.

The green comet was first discovered in January 2025 by the Mount Lemmon Survey, which uses a 60-inch telescope at Mt. Lemmon, Arizona. It takes about 1,350 years to complete one orbit around the Sun, but after November, that will be lowered to a mere 1,150 years.

SWAN was first discovered in September 2025 by the Solar and Heliospheric Observatory's SWAN instrument.

Comets are remnants from the early stages of the solar system, formed about 4.6 billion years ago, according to NASA. They consist primarily of ice mixed with dark organic material.

Upcoming comets to view

This celestial calendar includes significant comets that will approach Earth through the rest of 2025 and into early 2026 and can be seen with binoculars or a telescope.

Contributing: Lori Comstock – USA TODAY Network; Josh Kelly – The Oklahoman