Two Green Comets, One Evening Sky
Two green comets, Lemmon (C/2025 A6) and SWAN (C/2025 R2), are becoming easier to observe as they stretch into an energetic autumn display. After a Sunday appearance, both comets brighten and drift into favorable evening positions for skywatchers. On Monday, Oct. 13, 2025, Lemmon shifts from a morning-only target to an evening view, while SWAN settles into a southwest glow just beneath the bright star Sabik. Binoculars will reveal them for now, but their brightness grows as the moon wanes, and observers around the world may enjoy their best viewing window in the days ahead.
Best Times To Look On Monday, Oct. 13
The prime viewing window lasts about 30 minutes starting roughly 90 minutes after sunset. In New York City, where sunset hits at 6:16 p.m. EDT, aim for comparing twilight to darkness between 7:46 and 8:16 p.m. EDT. Lemmon will appear in the northwest, while SWAN sits in the southwest, offering a rare chance to contrast two green comets in a single sky.
Lemmon is still visible before dawn as well. A 30-minute morning window begins about 90 minutes before sunrise; with NYC sunrise at 7:05 a.m. EDT, the best time runs from roughly 5:35 to 6:05 a.m. EDT. In the northeast, just to the right of the Big Dipper’s handle, observers may catch Lemmon rising as Venus appears in the east—though the exact altitude varies with your location.
Where To Find Each Comet
Comet Lemmon (C/2025 A6) is moving through the northwest after sunset. From mid-northern latitudes, expect it to hover about 7 degrees above the northwest horizon around 7:46 p.m. EDT in New York, roughly the width of four fingers held at arm’s length. It will gradually descend as twilight fades. In the pre-dawn hours, Lemmon reappears in the northeast, near the Big Dipper’s handle and Alioth, climbing to about 24 degrees high around 5:35 a.m. EDT as the sky brightens with Venus rising in the east.
Comet SWAN (C/2025 R2) presents a bluish-green hue when viewed through binoculars. It will be visible in the southwestern sky, just below Sabik in Ophiuchus and above Antares in Scorpius. From New York, SWAN will appear roughly 19 degrees high, then sink toward the horizon as twilight deepens.
How To Photograph These Comets
Capturing Lemmon and SWAN requires a mix of planning and technique. Use a tripod-mounted camera or a smartphone in night mode with RAW if available. For a DSLR or mirrorless setup, start with an exposure of ISO 800–1600, an aperture of f/2.8–f/4, and shutter speeds of 2–5 seconds. In light-polluted areas, raise ISO slightly and shorten exposures. Use binoculars to locate the comets before framing, and focus manually on a bright star using live-view magnification or infinity focus. While tails may not be obvious to the naked eye, they often reveal themselves in long-exposure images.
Pro tip: scout with the binoculars first, then lock in your framing. A sequence of several 10–20 second shots can be stacked later to bring out faint comet tails and color while preserving detail in brighter sky regions.
What Makes This Week Special
The coming days are set to deliver some of the year’s best skywatching opportunities. Both Lemmon and SWAN are expected to peak around Oct. 20–21, a period that coincides with a new moon and the Orionid meteor shower. That combination may yield dark skies for the comets and the chance to enjoy meteor activity in a clear, dark autumn night—an event that could be memorable for casual observers and seasoned skywatchers alike.
Daily Comet Tracker and Tips
Check daily updates for finder charts, rise-and-set times, and viewing tips for Comet Lemmon and its companion. This ongoing guide helps you plan around cloud cover, twilight phases, and the changing night sky as autumn progresses, ensuring you don’t miss the best opportunities to see two green comets near bright stars.
Related Reading
For more on Lemmon and SWAN’s latest movements, including extended finder charts and best-practice viewing times, see trusted astronomy outlets and your local observatory notes. The upcoming Orionid meteor shower promises additional nighttime activity, making this your moment to experience a memorable celestial display.
