Overview
- Comets C/2025 A6 (Lemmon) and C/2025 R2 (SWAN) are at or near their brightest on Oct. 20–21 as they make close approaches to Earth, with SWAN around 24–24.5 million miles away and Lemmon roughly 55–56 million miles.
- The best viewing from the Northern Hemisphere is about 90 minutes after sunset, with a final predawn opportunity for Lemmon on Tuesday, Oct. 21.
- Lemmon is seen low in the northwest near the Big Dipper and bright star Arcturus, while SWAN sits in the southwest in Aquila beneath Altair of the Summer Triangle.
- Binoculars and dark skies are recommended, with Forbes reporting approximate magnitudes near +4.9 for Lemmon and +5.8 for SWAN.
- Live streams, including one by astronomer Gianluca Masi’s Virtual Telescope Project, are showcasing the pair as experts note comet brightness can change quickly and viewing will degrade as moonlight increases later this week.