Double comet sighting and meteor shower to brighten October skies

Two Bright Comets Could Light Up October Skies (Image: Canva)

Stargazers may be in for a rare treat. Two bright comets are expected to share the night sky in October, coinciding with a meteor shower.

What is Comet SWAN R2 and how was it discovered?
A long-tailed comet named C/2025 R2 (SWAN) was first spotted near the sun on 12 September. NASA’s Solar Dynamics Observatory detected the object with its SWAN instrument. Ukrainian amateur astronomer Vladimir Bezugly identified the comet in SWAN’s images. It was briefly labelled SWAN25B before the International Astronomical Union reclassified it as C/2025 R2 (SWAN).

The comet takes about 22,554 years to orbit the sun. Its bright tail stretches across a distance equal to five full moons. For now, it can be seen near Mars just after dusk, best viewed from the Southern Hemisphere.

When will SWAN R2 be closest to Earth?
On 21 October, SWAN R2 will pass just 0.27 astronomical units from Earth. That distance is roughly one quarter of Earth’s distance to the sun. At that point, astronomers expect it could shine at magnitude 4. This brightness would make it visible to the naked eye in dark skies. Even if it does not brighten enough, binoculars or telescopes will reveal the comet.

Earth may also cross its debris path between 4 and 6 October. This could bring a small, unique meteor shower.

What about Comet Lemmon’s appearance in October?
Comet C/2025 A6 (Lemmon) was discovered earlier this year. It will also reach its closest point on 21 October, about 0.60 astronomical units away. Like SWAN R2, it could reach magnitude 4 in brightness, making it visible without equipment.

The timing is especially striking because the Orionid meteor shower peaks on 20 and 21 October. Around 20 meteors per hour could be visible on those nights. With no moonlight to interfere, the sky will be particularly dark.

When was the last visible comet?
The last naked-eye comet was C/2020 F3 (NEOWISE), which delighted viewers in the summer of 2020. More recently, Comet C/2023 A3 (Tsuchinshan-ATLAS) appeared through binoculars in October 2024.

Now, the possibility of seeing two bright comets alongside a meteor shower makes October a month to watch for skywatchers.