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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.
Stellarium
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