Finally See Comet Lemmon On Sunday Before It’s Gone For 1,150 Years

Topline

If you’ve not seen the two green comets yet, 90 minutes after sunset on Sunday, Oct. 26, is your last best chance before they fade. The brighter Comet Lemmon (C/2025 A6) and much dimmer Comet SWAN (C/2025 R2) are now barreling away from Earth, reducing in brightness as they do, while a 24%-lit waxing crescent moon is on the cusp of making comet-observing significantly more difficult. With Lemmon in the northwestern sky and SWAN below the Summer Triangle stars in the south, near Saturn, it’s time to grab a pair of binoculars and take a look — or wait for 1,150 years.

Key Facts

When And Where To See The Comets

The best time to spot Comet Lemmon and Comet SWAN on Sunday, Oct. 26, 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 5:56 p.m. EDT, the ideal time for evening viewing is 7:26-7:56 p.m. EDT. A 24%-lit waxing crescent moon will be low in the southwest, setting early, so both comets benefit from dark conditions before the moon brightens later in the week.

How To Find Comet Lemmon

Distance from the sun: 56.9 million miles (91.6 million kilometers)

Distance from Earth: 59.8 million miles (96.2 million kilometers)

After sunset on Sunday, Oct. 26, look for Comet Lemmon due west, above-left of bright star Arcturus, low on the west-northwest horizon. Trace the stars in the Big Dipper’s curved handle and go in an “arc to Arcturus.” Now go in a right angle to the next bright star, Rasalhague, the brightest in the vast constellation Ophiuchus. Comet Lemmon will be directly below the bright star Vega, high above. Its height above the horizon varies by location, but from New York, the comet will appear about 21 degrees up at 7:26 p.m. EDT and will gradually sink as twilight deepens.

How To Find Comet Swan

Distance from the sun: 101.2 million miles (162.9 million kilometers)

Distance from Earth: 27.8 million miles (44.8 million kilometers)

Comet SWAN will be visible in binoculars on Sunday, Oct. 26, low in the south after sunset. SWAN will be in the constellation Aquarius, below and to the left of the bright star Altair in the Summer Triangle. You’ll find it between Altair and Fomalhaut, a bright star closer to the horizon. The comet’s height above the horizon will vary depending on your location, but from New York, it will be around 45 degrees up as it becomes visible.

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.

Further Reading

ForbesComet Tracker For Thursday: It’s Finally Time To See Rare Twin CometsBy Jamie CarterForbesA Once-In-A-Lifetime Green Comet May Soon Be Visible, Scientists SayBy Jamie CarterForbesSee Rare Sight Of Two Comets As Meteor Shower Peaks — Here’s WhenBy Jamie CarterForbesComet Lemmon: Your Ultimate Viewing Guide To The ‘Comet Of The Year’By Jamie CarterForbesTwo Naked Eye Comets, ‘Harvest Moon’ And Fireballs: October’s Night SkyBy Jamie CarterForbesOrionid Meteor Shower Begins Thursday — When To See It At Its Best With Two CometsBy Jamie CarterForbesI Just Saw And Photographed The Comet — Here’s How You Can TooBy Jamie Carter