Skywatchers, rejoice. This month, not one but two comets are set to soar into our night skies for your viewing pleasure.
The two comets, C/2025 R2 (SWAN) and C/2025 A6 (Lemmon), were both discovered in 2025. The celestial visitors are gearing up for a close flyby of Earth in October, becoming more visible as they approach our planet. SWAN will be closest to Earth on October 19, while Lemmon is set for its own close approach on October 21. Both icy comets may even be visible to the naked eye around that time.
Cosmic pair
Astronomers spotted Lemmon in January using the Mt. Lemmon SkyCenter observatory in Arizona’s Santa Catalina Mountains. The comet was speeding toward the inner solar system at speeds up to 130,000 miles per hour (209,000 kilometers per hour).
Later in September, amateur astronomer Vladimir Bezugly discovered comet SWAN in images from the SWAN instrument on NASA’s SOHO satellite. The comet became significantly brighter as it emerged from the Sun’s direction.
At its closest approach, SWAN will be at a distance of approximately 24 million miles (39 million kilometers) from our planet, or about a quarter of the distance between the Sun and Earth. SWAN is now at a brightness magnitude of around 5.9, according to EarthSky. The unexpectedly bright comet is currently in the southern skies, but it is slowly moving north, according to NASA.
Following SWAN’s closest approach, comet Lemmon will be right behind. The comet will be about half the distance between the Sun and Earth before rounding the Sun on November 8. From there, it will begin its next journey around the star. Lemmon will continue to brighten as it approaches the Sun, but it will likely stay visible, and possibly become even brighter, around October 31 to November 1, according to EarthSky.
How to see SWAN and Lemmon
SWAN is best viewed in the Southern Hemisphere. The comet crossed into the Libra constellation on September 28, and will make its way across Scorpius on October 10. Around October 9-10, it will appear near Beta Librae, the brightest star in the Libra constellation, EarthSky reports.
It may, however, be a bit tricky to spot because its position in the skies will be close to the setting Sun. Sky watchers hoping to catch a glimpse of SWAN need up toward the west after sunset.
Conditions are more favorable for Lemmon. The comet is best viewed in the Northern Hemisphere, where it will be positioned near the Big Dipper for most of October. Sky watchers should look to the eastern skies just before sunrise to spot the comet.
By mid-October, the comet may be easier to view. On October 16, Lemmon will pass near Cor Caroli, a binary star system in the northern constellation of Canes Venatici, according to EarthSky. Around that time, the comet could be visible to the naked eye.
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