Two Comets Set to Illuminate Night Skies This October

Skywatchers around the world will have the opportunity to view two comets this month as they approach Earth. The comets, C/2025 R2 (SWAN) and C/2025 A6 (Lemmon), were both discovered in 2025 and are expected to become increasingly visible from Earth as they make their close approaches. SWAN will reach its nearest point to Earth on October 19, followed by Lemmon on October 21.

Discovery and Trajectories

Astronomers first identified Lemmon in January at the Mt. Lemmon SkyCenter in Arizona, where it was observed hurtling towards the inner solar system at impressive speeds of up to 130,000 miles per hour (approximately 209,000 kilometers per hour). Later in September, amateur astronomer Vladimir Bezugly discovered SWAN using images from NASA’s SOHO satellite, where it appeared brighter as it emerged from the Sun’s glare.

During its closest approach, SWAN will come within about 24 million miles (around 39 million kilometers) of Earth, representing a quarter of the distance between our planet and the Sun. Currently, SWAN has a brightness magnitude of approximately 5.9, making it visible with the naked eye under the right conditions. As it moves northward from the southern skies, it is anticipated to become an eye-catching spectacle.

Following SWAN‘s approach, Lemmon will come within half the distance from the Sun to Earth before rounding the Sun on November 8. As it approaches, Lemmon is expected to brighten further and may remain visible through the end of October.

Viewing Opportunities

For those wishing to catch a glimpse of SWAN, the best viewing conditions will be in the Southern Hemisphere. As of September 28, SWAN crossed into the Libra constellation and is expected to traverse Scorpius around October 10. On October 9 and 10, skywatchers can look for it near Beta Librae, the brightest star in Libra, though its proximity to the setting Sun may make it challenging to spot. Observers should look toward the western horizon just after sunset.

In contrast, Lemmon is best viewed from the Northern Hemisphere, where it will be located near the Big Dipper throughout much of October. The ideal time for viewing will be just before sunrise in the eastern sky. By mid-October, visibility may improve, particularly on October 16, when Lemmon will pass near Cor Caroli, a noted binary star system in the Canes Venatici constellation.

Both comets offer a rare opportunity for amateur astronomers and the general public alike to witness the beauty of our solar system. As they journey closer to Earth, enthusiasts are encouraged to take advantage of the favorable conditions for viewing these spectacular celestial visitors.