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Two green comets will shine together – perhaps with the naked eye – around October 20 and 21, as the Orionid meteor shower peaks. However, if you want a glimpse, comets Lemmon (C/2025 A6) and SWAN (C/2025 R2) are now visible from the Northern Hemisphere with binoculars or a small telescope. Here’s how to find them on Friday October 10, 2025.
Comet C/2023 A3 (Tsuchinshan-ATLAS) crosses the sky on October 23, 2024 in Lhasa, Xizang Autonomous Region of China. (Photo by Jiang Feibo/China News Service/VCG via Getty Images)
Chinese News Service via Getty Images
Key facts
Of the two, Comet Lemmon is currently the brighter. It last entered the inner solar system about 1,350 years ago and will do so again around 3175. Comet SWAN takes about 22,554 years to orbit the sun and its next visit will be in 24,579. These are the first comets visible through binoculars since Comet Tsuchinshan-ATLAS in October 2024.
Dark skies to the north and west are ideal for observing comets. Comet Lemmon will be visible before sunrise in the northeast near the Big Dipper on Friday, while an 86%-illuminated waning gibbous moon shines in the west. Comet SWAN will be low in the southwest after sunset.
In a pair of binoculars, comets appear as a small, diffuse spot that changes position slightly each day. Comet Lemmon is moving very quickly and will also be visible early next week in the night sky after sunset.
Over the next two weeks, both comets are expected to become brighter as they approach Earth between October 20 and 23.
A search map of Comet Lemmon for October 10, 2025 and the following two weeks, courtesy of In-The-Sky.org.
In-The-Sky.com (used with permission)
Comet Lemmon: when and where to find it on Friday October 10, 2025.
Distance from the sun: 78.3 million miles (126 million kilometers)
Distance from Earth: 70.7 million miles (113.8 million kilometers)
On Friday, October 10, 2025, Comet Lemmon will be visible in the northeast before dawn on the right side of the Big Dipper, low in the sky but observable with binoculars. It will be about halfway between the stars Dubhe and Merak outside the bowl of the Big Dipper and the bright star Regulus in the constellation Leo, according to search maps at In-The-Sky.com.
Comet Lemmon: when and where to find it on Friday October 10, 2025.
Stellarium
Comet Lemmon: best time to observe
The best time to look for Comet Lemmon will be a 30-minute window starting about 90 minutes before sunrise where you are. For New York, sunrise is at 7:02 a.m. EDT, so the ideal viewing time will be 5:32 a.m. to 6:02 a.m. EDT (Venus will rise in the east during this time), although you can watch earlier. The height of the comet above the horizon will vary depending on your location, but from New York it will be about 30 degrees (about the width of your hand’s span, with fingers extended, held at arm’s length) and rising. In addition to battling the growing light of dawn, on Thursday you will also have to contend with the light of the waning gibbous moon, 86% illuminated, setting in the west.
A search map of Comet SWAN R2 for October 10, 2025 and the following two weeks, courtesy of In-The-Sky.org.
In-The-Sky.com (used with permission)
Comet Swan: when and where to find it on Friday October 10, 2025.
Distance from the sun: 76.1 million miles (122.4 million kilometers)
Distance from Earth: 30.4 million miles (48.9 million kilometers)
The bluish-green comet SWAN – discovered only in September – will be visible through binoculars on Friday, October 10, 2025, in the southwest after sunset, to the right of the bright star Antares in the constellation Scorpius. It will be in line with the trio of bright stars that outline Scorpio’s head, according to search maps on In-The-Sky.com.
Comet Swan: when and where to find it on Friday October 10, 2025.
Stellarium
Comet Swan: best time to observe
The best time to look for Comet SWAN will be a 30-minute window starting about 90 minutes after sunset where you are. For New York City, sunset is at 6:21 p.m. EDT, so the ideal viewing time will be 7:51 p.m. to 8:21 p.m. EDT. The comet’s height above the horizon will vary depending on your location, but from New York it will be about 13 degrees (about the width between your little and index fingers held at arm’s length) and will sink.
How bright are comets?
Comets Lemmon and SWAN are currently shining in the mag. 5.8 and mag. 6, respectively, according to the Comet Observations Database, which places them at the limit of naked-eye visibility – although very dark skies are required. In practice, you will need binoculars – preferably 8×42 to 10×50 or similar – or a small telescope (through which you can see traces of a tail about a degree in length). Bursts or lulls can quickly change apparent brightness, so take advantage of them while you can.
What Jupiter did to Comet Lemmon
In April 2025, Comet Lemmon passed approximately 348 million kilometers from Jupiter. It may seem like a long time ago, but the gas giant’s immense gravity pulled on the comet, changing its orbit. According to Space.com, Jupiter drained some of Lemmon’s orbital energy, shortening its period by almost 200 years. Instead of going back in time every 1,350 years, the return will now take place in approximately 1,150 years. Jupiter often acts as a “cosmic gatekeeper,” reshaping the orbits of passing comets, sometimes capturing them, sometimes ejecting them from the solar system entirely.
Check my feed every day this month for a daily “comet tracker” with search maps and tips for observing Comet Lemmon and Comet SWAN.
