Topline
Are you ready to spot two green comets? Visible in the pre-dawn hours for some weeks, the brightest of two comets now in the night sky — Comet Lemmon — on Sunday, Oct. 12, 2025, should become easier to see after its dimmer appearance on Saturday, Oct. 11. A diffuse fuzzy patch in the northwestern sky in binoculars, Lemmon is joined by the slightly less bright Comet SWAN in the southwest in the post-sunset night sky. Both comets will likely brighten through the week as the moon recedes from the evening sky, reaching their brightest around Oct. 20-21 as the Orionid meteor shower peaks. Here’s how to find C/2025 A6 (Lemmon) — and perhaps C/2025 R2 (SWAN) — on Sunday, Oct. 12, 2025.
Key Facts
There are two comets currently observable in binoculars — the brightest, Comet Lemmon, before sunrise in the northern sky and the dimmer Comet SWAN after sunset in the southwestern sky.
Views of both will be slightly affected by the light of a 65%-lit waning gibbous moon, but the best time to view them through binoculars is 90 minutes before sunrise and 90 minutes after sunset, respectively.
Comet Lemmon and its gas tail are brightening rapidly in the predawn sky, according to Space.com, but it’s likely to reach its brightest in late October when it gets around 55.4 million miles (89.2 million kilometers) from Earth. The Comet Observation database reported it to be shining at magnitude +5.7 on Oct. 9. Comet SWAN is reported to be a little dimmer at magnitude +6.
Both comets will appear as small, diffuse patches in a pair of binoculars, changing position slightly each day. Those observing in dark sky places far from streetlights and urban light pollution will have the best views of both comets.
Lemmon and SWAN are the first comets widely visible in binoculars since Comet Tsuchinshan-ATLAS in October 2024.
Comet Lemmon: When And Where To Find It On Sunday, Oct. 12, 2025.
Distance from the sun: 75.3 million miles (121.2 million kilometers)
Distance from Earth: 66 million miles (106.3 million kilometers)
On Sunday, Oct. 12, 2025, Comet Lemmon will be visible in the northeast before dawn to the right-hand side of the Big Dipper, low in the sky but observable in binoculars. It will be roughly halfway between the stars Megrez and Phecda on the inside of the Big Dipper’s bowl, and Alula Borealis and Alula Australis, two bright stars that mark the foot of the constellation Ursa Major, “the Great Bear.” You can find some excellent finder charts at In-The-Sky.com.
Comet Lemmon: Best Time To See It
The best time to look for Comet Lemmon will be a 30-minute window beginning about 90 minutes before sunrise where you are. For New York City, sunrise is 7:04 a.m. EDT, so the ideal viewing time will be 5:35-6:05 a.m. EDT (Venus will rise in the east during this time), although you can look earlier. The comet’s height above the horizon will vary depending on your location, but from New York, it will be around 27 degrees up (about the width of the span of your hand, with fingers stretched out, held at arm’s length) and rising. In addition to fighting the increasing light of dawn, on Thursday, there’s also the light of the 65%-lit waning gibbous moon, setting in the west, to contend with. From early next week, Comet Lemmon will also be visible in the post-sunset night sky.
Comet Swan: When And Where To Find It On Sunday, Oct. 12, 2025
Distance from the sun: 79.2 million miles (127.4 million kilometers)
Distance from Earth: 28.1 million miles (45.3 million kilometers)
Blueish-green Comet SWAN — only discovered in September — will be visible in binoculars on Sunday, Oct. 12, 2025, low in the southwest after sunset, above the bright star Antares in the constellation Scorpius. You can find some excellent finder charts at In-The-Sky.com.
Comet Swan: Best Time To See It
The best time to look for Comet SWAN will be a 30-minute window beginning about 90 minutes after sunset where you are. For New York City, sunset is 6:17 p.m. EDT, so the ideal viewing time will be 7:47-8:17 p.m. EDT (though you can begin looking shortly before). The comet’s height above the horizon will vary depending on your location, but from New York, it will be around 17 degrees up (about the width between your little finger and forefinger held at arm’s length) and sinking.
Rare Visitors From The Outer Solar System
Both comets are on different journeys. Comet Lemmon was last in the inner solar system around the year 675, and its next visit is expected to take place around 3175. It’s currently approaching Earth, which it will get closest to on Oct. 21 (63 million miles/102 million kilometers) before it reaches perihelion — closest to the sun — on Nov. 8. Comet SWAN is a much longer-period comet, taking about 22,554 years to orbit the sun. It won’t visit again until 24,579. It was discovered in September, when it appeared in images of the sun as it exited its perihelion. It will get closest to Earth on Oct. 20 (24 million miles/39 million kilometers).
Check my feed every day this month for a daily “comet tracker” with finder charts and tips for viewing Comet Lemmon and Comet SWAN.