ByJamie Carter,
Senior Contributor.
This weekend offers the last best chance to see the two green comets before they’re lost in a brightening moon. On Saturday, Oct. 25, Comet Lemmon (C/2025 A6) continues westward, entering the constellation Serpens in the northwestern sky, while Comet SWAN (C/2025 R2) hangs below the Summer Triangle stars in the south, near Saturn. It’s the best remaining night to catch them before they fade and the 16 %-lit waxing crescent moon begins to bleach the twilight sky.
The brighter Comet Lemmon is visible in the northwest in Serpens, and Comet SWAN in the southwest in Aquarius, about 90 minutes after sunset. Lemmon is moving quickly west of the Big Dipper, near bright Arcturus, while the dimmer SWAN lies beneath the three stars that form the Summer Triangle.
As the moon brightens, this weekend is the last best time to view both comets—though either could still surprise observers with a sudden outburst. Use stargazing apps such as Sky Guide, Stellarium, or SkySafari, or finder charts at In-The-Sky.com. Through binoculars (8×42 or 10×50 recommended), each appears as a diffuse, fuzzy patch with a faint tail. The best views will be had far from light pollution in a Dark Sky Place (or somewhere that looks dark on a light pollution map).
