Overview
- Comet C/2025 A6 (Lemmon) reaches its nearest approach to Earth around Oct. 21 at roughly 55–56 million miles and is near peak apparent brightness before perihelion in early November.
- Comet C/2025 R2 (SWAN) passed closer on Oct. 20 at about 24–25 million miles yet remains fainter and typically requires binoculars or a telescope.
- The prime viewing window is about 90 minutes after sunset with brief optimal periods; Lemmon sits low in the northwest near Arcturus and the Big Dipper, while SWAN is low in the southwest below Altair.
- Astrophotographers have documented Lemmon’s green coma and solar‑wind effects, including ripples and temporary tail disconnection events captured in mid‑October.
- A dark, near‑new‑moon sky and the Orionid meteor shower enhance opportunities this week, though local cloud cover and increasing moonlight later in the week may reduce visibility.