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The green comets visible in the night sky are now at their minimum distance from Earth, so they should be at their brightest in the night sky. Comet Lemmon (also called C/2025 A6) and Comet SWAN (C/2025 R2) are the first comets visible in binoculars since Comet Tsuchinshan-ATLAS in October 2024. Both are visible after sunset from the Northern Hemisphere, but Tuesday, Oct. 21, is the last chance to also see Lemmon before sunrise.

Comet Neowise passes St Mary’s Lighthouse in Whitley Bay in the early hours of Tuesday morning. (Photo by Owen Humphreys/PA Images via Getty Images)

PA Images via Getty ImagesKey Facts

Although both Lemmon and SWAN reached their brightest on Monday, Oct. 20, when they reached their closest to Earth at 55 and 24 million miles, respectively, they are likely to remain at their brightest on Tuesday, Oct. 21.

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 while SWAN is beneath the three bright stars that comprise the Summer Triangle.

Use the finder charts at In-The-Sky.com or stargazing apps such as Sky Guide, Stellarium and SkySafari to easily find the location of the comets in the night sky.

Comet Lemmon and Comet SWAN are most easily seen using binoculars and away from light pollution in a Dark Sky Place (or somewhere that looks dark on a light pollution map). They’re shining at about magnitude +4.9 and +5.8, respectively.

If you’re yet to see the comets, try this week because the brightness of comets can quickly change, either undergoing an outburst and brightening, or disintegrating and fading. By the weekend, strong moonlight will make the comets tougher to see.

The best time to see Comet Lemmon on Oct. 21 will be 90 minutes before sunrise.

StellariumWhen And Where To See The Comets

The best time to spot Comet Lemmon and Comet SWAN on Tuesday, Oct. 21, 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 6:03 p.m. EDT, the ideal time for evening viewing is 7:33-8:03 p.m. EDT.

Comet Lemmon can also be seen before dawn — though not after Tuesday. With sunrise at 7:15 a.m. EDT in New York, the best time will be 6:00-6:15 a.m. EDT.

The best time to see Comet Lemmon on Oct. 21 will be 90 minutes after sunset.

StellariumHow To Find Comet Lemmon

Distance from the sun: 62.8 million miles (101.1 million kilometers)

Distance from Earth: 55.4 million miles (89.2 million kilometers)

Before sunrise, the comet will be in the northeast. The Big Dipper’s handle — which will point down toward the horizon — can be used to find it. Trace the stars of the Big Dipper’s handle in an arc, or banana-shape, to go in a curve down to the north-east horizon. From New York, the comet will stand about 6 degrees high at 6:00 a.m. EDT, and though it will climb higher as dawn approaches, after about 15 minutes, the sky will be bleached. Venus rises at about the same time.

After sunset on Tuesday, Oct. 21, look for Comet Lemmon above-right of bright star Arcturus, low on the northwest horizon. Its height above the horizon varies by location, but from New York, the comet will appear about 18 degrees above the northwest horizon at 7:33 p.m. EDT — roughly the width of four outstretched fingers held at arm’s length — and will gradually sink as twilight deepens.

The best time to see Comet SWAN on Oct. 21 will be 90 minutes after sunset.

StellariumHow To Find Comet Swan

Distance from the sun: 93.3 million miles (150.2 million kilometers)

Distance from Earth: 24.5 million miles (39.5 million kilometers)

Bluish-green Comet SWAN will glow in binoculars low in the south-west after sunset, now in Aquila beneath the bright star Altair of the Summer Triangle. It lies in front of the Milky Way’s dense star fields, which will be visible behind the comet in binoculars. The comet’s height above the horizon will vary depending on your location, but from New York at 7:33 p.m. EDT, it will be around 38 degrees up as it becomes visible.

How to find Comet Lemmon, 90 minutes after sunset, from Oct. 13-31, 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.

Further ReadingForbesComet 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