Topline
The two green comets continue to shine brightly in twilight each evening for lucky skywatchers with binoculars in the Northern Hemisphere. For observers on Friday, Oct. 24, the bright Comet Lemmon (C/2025 A6) continues to travel westward through the constellation Boötes in the northwestern sky while the dimmer Comet SWAN (C/2025 R2 (SWAN)) hangs below the Summer Triangle stars in the southwest. It’s the best remaining night to see them because they’re now receding from Earth — and the 10%-lit waxing crescent moon will brighten later in the week, bleaching the night sky and making the comets harder to see.
Comet Lemmon ‘C/2025 A6’ as it shines among the stars in the night in the sky over Debrad, Slovakia on October 20, 2025. (Photo by Robert Nemeti/Anadolu via Getty Images)
Anadolu via Getty Images
Key Facts
Comet Lemmon was first discovered on Jan. 3, 2025, by the Mount Lemmon Survey near Tucson, Arizona, and will get closest to the sun on Nov. 8. Comet SWAN was only found on Sept. 11, 2025, as it looped around the sun.
Both Lemmon and SWAN are long-period comets from the Oort Cloud, a sphere of millions of comets wrapped around the solar system. Lemmon was last in the inner solar system in the year 875 and is expected back around 3175. SWAN is on a much longer journey, taking about 20,000 years to orbit the sun.
The comets are visible in the northwest (Lemmon) and southwest (SWAN) about 90 minutes after sunset. Lemmon is moving quickly across the sky west of the Big Dipper, close to bright star Arcturus, while SWAN is beneath the three bright stars that comprise the Summer Triangle. The best way to find the comets is stargazing apps such as Sky Guide, Stellarium and SkySafari, or the finder charts at In-The-Sky.com.
In binoculars (8×42 or 10×50 are recommended), they look like a diffuse, fuzzy patch with a 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).
The moon is about to make both comets harder to see, and by the weekend, both comets are likely to have faded slightly. As always, comets can have a surprise outburst and brighten or a sudden disintegration and fade.
How to find Comet Lemmon, 90 minutes after sunset, from Oct. 13-24, 2025.
Stellarium
When And Where To See The Comets
The best time to spot Comet Lemmon and Comet SWAN on Friday, Oct. 24, is during a 30-minute window starting about 90 minutes after sunset where you are. Both are visible after sunset but in opposite parts of the sky — Lemmon in the northwest, SWAN in the southwest. For New York City, where sunset is at 5:59 p.m. EDT, the ideal time for evening viewing is 7:29-7:59 p.m. EDT. A 10%-lit waxing crescent moon will be sinking into the southwest at that time, leaving most of the sky dark — excellent conditions for observing both comets.
Where to find Comet Lemmon after sunset on Oct. 24, 2025.
Stellarium
How To Find Comet Lemmon
Distance from the sun: 59.2 million miles (95.2 million kilometers)
Distance from Earth: 57.1 million miles (91.9 million kilometers)
After sunset on Friday, Oct. 24, look for Comet Lemmon above-left above bright star Arcturus low on the northwest horizon. Trace the stars in the Big Dipper’s curved handle and go in an “arc to Arcturus.” Now go a couple of degrees above Arcturus to the next bright star, Izar. Comet Lemmon will be about four degrees to the right of Izar and four degrees below Alpehcca in Corona Borealis. Its height above the horizon varies by location, but from New York, the comet will appear about 20 degrees above the northwest horizon at 7:29 p.m. EDT and will gradually sink as twilight deepens.
How to find Comet Lemmon, 90 minutes after sunset, from Oct. 13-31, 2025.
Stellarium
How To Find Comet Swan
Distance from the sun: 98.1 million miles (157.9 million kilometers)
Distance from Earth: 26.1 million miles (42 million kilometers)
Blueish-green Comet SWAN will be visible in binoculars on Friday, Oct. 24, 2026, low in the south after sunset. SWAN will be in the constellation Aquila, above the famous “Teapot” asterism in the constellation Sagittarius, and below and to the left of the bright star Altair in the Summer Triangle. The comet’s height above the horizon will vary depending on your location, but from New York, it will be around 43 degrees up as it becomes visible.
Both comets will remain visible for another few evenings, but bright moonlight will quickly begin to wash them out by the weekend.
Where to find Comet SWAN after sunset on Oct. 24, 2025.
Stellarium
Check my feed every day this month for a daily “comet tracker” with finder charts and tips for viewing Comet Lemmon and Comet SWAN from mid-northern latitudes. Also read How To Photograph The Green Comets, Best Stargazing Apps For Finding The Comets and 25 Dark Sky Parks In The U.S. To See The Comets.
