Overview

• Swan (C/2025 R2) will come to about 30 million kilometers from Earth and is forecast to reach maximum brightness on October 19–20.
• The comet will sit low in the evening sky from mid‑October, climb higher as it quickly fades, and likely slip from view in early November.
• Lemmon (C/2025 A6) will be nearest around October 21 at roughly 90 million kilometers and is expected to be brightest between October 28 and 31.
• Lemmon is already high before dawn and will sweep through several constellations, including Ursa Major, with naked‑eye visibility possible from dark sites.
• Astronomers highlight the challenge of detecting objects arriving from the Sun’s direction, citing the 2013 Chelyabinsk airburst, and point to planned space telescopes for better early warning.