Overview: Twin Green Comets Gracing the Evening Sky
Two emerald-hued comets are gracing the evening sky in mid-October 2025, offering skywatchers a rare chance to spot them with binoculars. Comet Lemmon (C/2025 A6) is shifting from morning to evening visibility, while Comet SWAN (C/2025 R2) remains a binocular-friendly target low in the southwestern sky. Both are expected to brighten around Oct. 20–21, a period that coincides with a new moon and the Orionid meteor shower, potentially making this one of the best observing windows of the year.
Best Times To Look: October 13–21, 2025
The practical viewing window for both comets is about 30 minutes, roughly 90 minutes after sunset or before sunrise, depending on location. On Monday, Oct. 13, observers in much of the northern hemisphere can catch Lemmon in the northwest after sunset and SWAN in the southwest beneath a bright star in Ophiuchus. For New York City, with sunset around 6:16 p.m. EDT, the ideal evening period falls roughly between 7:46 and 8:16 p.m. EDT, when both comets are yet to sink below the horizon.
Lemmon is also visible before dawn, rising in the northeast, to the right of the Big Dipper’s handle and near the star Alioth. In New York, expect a 5:35–6:05 a.m. EDT window for pre-dawn views as Venus climbs in the east and the sky brightens toward sunrise.
Where to Find Comet Lemmon (C/2025 A6)
After sunset, Lemmon appears low in the northwest, just below the curved handle of the Big Dipper. From mid-northern latitudes, it hovers around 7 degrees above the horizon at the start of the prime evening window, gradually sinking as twilight deepens. Distance estimates place Lemmon at about 74 million miles from the Sun and roughly 64 million miles from Earth, making it a relatively nearby visitor on the cosmic stage.
Where to Find Comet SWAN (C/2025 R2)
Blue-green in color, SWAN remains a binocular object as it glides through the southwestern sky on the same evening. It tracks low near Sabik, a bright star in Ophiuchus, and just above Antares in Scorpius. From New York, SWAN’s altitude is expected to be around 19 degrees after sunset, a comfortable height for binoculars that allows a steady view as it moves with the sky’s rotation.
Practical Tips for Binocular and Telescope Viewers
– Start with a comfortable, stable stance and use both eyes to spot low-contrast details. Binoculars are ideal for initial locating and for appreciating the comets’ overall glow.
– If you’re photographing, frame each comet separately to avoid overloading a single shot. For long exposures, a tripod and a camera with manual controls deliver the best results.
– Check moonlight conditions: with a waning gibbous moon rising later at night, darker skies later in the evening will help both comets stand out more clearly.
Photography Tips: Capturing the Green Glow
To photograph the comets, you can use a smartphone in night mode or a DSLR/mirrorless camera on a tripod. For best results with a conventional setup, try a 50–105 mm lens, ISO 800–1600, aperture f/2.8–f/4, and shutter speeds of 2–5 seconds. Start with a longer exposure for Lemmon, then slightly shorten for SWAN if trails become excessive in light-polluted areas. Use live-view magnification to focus on a bright star and then lock focus for consistent shots. Even when the tails aren’t stark in the naked eye, they often reveal themselves in photographs.
Looking Ahead: A Week of Prime Skies
As Oct. 20–21 approaches, both Lemmon and SWAN are forecast to reach their brightest, aligning with a new moon and the Orionid meteor shower. With careful timing and dark-sky locations, observers could enjoy a rare, vivid display of two green comets in the same sky, a retirement-worthy highlight for any stargazing calendar.
Daily Sky Tracking and Resources
For ongoing updates, follow daily comet tracker tips and finder charts. Local weather and light-pollution levels will influence visibility, so check current conditions before heading out.
