**Rare Comets Light Up October Skies: How and When to See Them**
Two rare comets are currently streaking across the night sky, providing a unique spectacle for skywatchers this October. Comets C/2025 A6 (Lemmon) and C/2025 R2 (SWAN) are making their closest approach to Earth, and both have reached their peak brightness on October 20 and 21. Although they have now passed their brightest phase, there are still opportunities to catch a glimpse of these celestial wonders during the final days of the month.
### Once-in-a-Lifetime Sightings
What makes these comets particularly special is their rarity. According to astronomers, neither comet will return to our skies anytime soon. SWAN will not be visible from Earth again for another 650 to 700 years, while Lemmon’s next appearance won’t be for approximately 1,300 years. As Jason Steffen, an assistant professor of physics and astronomy at the University of Nevada, Las Vegas (UNLV), explains, Comet Lemmon is classified as a “non-periodic” comet. This means its orbit is highly elliptical and unpredictable, in contrast to comets like Halley’s Comet, which returns every 76 years. The last time Lemmon visited Earth was in the 8th century.
### Discovery and Characteristics
Both Lemmon and SWAN were discovered in 2025, and their names reflect their origins. Lemmon was identified on January 3 by the Mount Lemmon Survey, a project based in Arizona that uses a 60-inch telescope to scan the sky for celestial objects. The survey's work is part of a broader effort to catalog and track asteroids and comets that might pass close to Earth.
Comet SWAN was discovered later in the year, on September 11, by Vladimir Bezugly, an amateur astronomer from Ukraine. Bezugly spotted the comet in images taken by the Solar Wind ANisotropies (SWAN) instrument aboard the Solar and Heliospheric Observatory, a spacecraft that studies the sun and solar wind from space. Bezugly noted that SWAN was relatively easy to detect, thanks to its brightness in the ultraviolet band and its central location in the SWAN instrument’s images. Remarkably, this is the 20th comet discovered using the SWAN instrument.
Both comets are particularly striking in appearance: they shine with a characteristic green glow, a result of the gases in their comas fluorescing under the sun’s ultraviolet light. Each also sports a long, streaming tail, making them especially photogenic and exciting targets for amateur astronomers and photographers.
### How to See the Comets
Although the comets have already been at their brightest, it is still possible to see them in the sky through the end of October. Comet Lemmon is the easier of the two to spot without any special equipment. In locations with dark skies and minimal light pollution, it may