Comet C/2025 A6 (Lemmon) makes its closest approach to Earth today—won't return for another 1,300 years

The comet is offering viewers in 2025 their absolute best chance for a sighting before it disappears from sight for the next 1,300 years.
Comet C/2025 A6 (Lemmon) with a glowing green coma and visible tail navigating across millions of stars in the Solar System (Cover Image Source: Getty | Javier Zayas Photography)
Comet C/2025 A6 (Lemmon) with a glowing green coma and visible tail navigating across millions of stars in the Solar System (Cover Image Source: Getty | Javier Zayas Photography)

A once-in-a-millennium celestial event is peaking today as Comet C/2025 A6 (Lemmon) makes its closest pass to Earth. Discovered just this past January, the comet is offering observers in 2025 their best opportunity for a sighting before it recedes from view for the next 1,300 years, as per The Royal Astronomical Society. 

Comet Lemmon is brightening and moving into morning northern skies (Cover Image Source: NASA APOD | Victor Sabet, Julien De Winter)
Comet Lemmon is brightening and moving into morning northern skies (Image Source: NASA APOD | Victor Sabet, Julien De Winter)

The comet is at its "best visibility right now," according to Dr. Robert Massey, deputy executive director of the Royal Astronomical Society. While it reaches its closest point to our planet on October 21 and its closest approach to the Sun around November 4th, skygazers should look to the evening sky immediately following sunset. For optimal viewing, Dr. Massey advises watching as the sky darkens. The comet will be moving first past the bright star Arcturus, and then shifting southwest, beneath the stars of the Summer Triangle.

While it's a reasonably bright comet, it will likely appear as a "fairly bright, fuzzy object" and may require binoculars to be seen easily. Experts caution that it will not be as spectacularly visible as Comet Hale-Bopp in the late 1990s or NEOWISE in 2020. However, the ease of viewing with binoculars makes it a unique and recommended target, especially for those who have never observed a comet before.

C/2020 F3 (NEOWISE), or Comet NEOWISE, is a retrograde comet with a near-parabolic orbit discovered on March 27, 2020 (Representative Cover Image Source: Getty | Javier Zayas Photography)
C/2020 F3 (NEOWISE), or Comet NEOWISE, is a retrograde comet with a near-parabolic orbit discovered on March 27, 2020 (Representative Image Source: Getty | Javier Zayas Photography)

The comet's appearance is perfectly timed to coincide with the Orionid meteor shower, which is also peaking around October 21. This annual shower, visible until November 7, is produced as the Earth passes through the trail of debris left by Halley's Comet. The swift entry of this cosmic dust into our atmosphere creates the characteristic bright streaks known as "shooting stars." 

A telescopic close-up of a comet.
(Representative Cover Image Source: Getty Images | Alan Dyer/Stocktrek Images.)
A telescopic close-up of a comet. (Representative Image Source: Getty Images | Alan Dyer/Stocktrek Images.)

For those unable to experience this celestial wonder in person, a live feed is being provided by The Virtual Telescope Project, offering a remote view of the comet's rare appearance.

Comet C/2025 A6 (Lemmon) is far more than a simple chunk of ice; it is a profound "time traveler," making its first reappearance in the inner solar system in an estimated 1,350 years. Its incredible voyage began approximately 240 astronomical units from the Sun, well beyond Pluto, before the Sun's gravity began to draw it inward. This long, elliptical path is a stark demonstration of the immense and dynamic scale of our solar system. Astronomers note that its orbit is actually shortening, a cosmic process that underscores the ever-changing nature of the bodies in our stellar neighborhood.

Comet C/2025 A6 (Lemmon) on 17 September 2025 (Image Source: Flickr | dkatevenis)
Comet C/2025 A6 (Lemmon) on 17 September 2025 (Image Source: Flickr | dkatevenis)

When the comet was first spotted by a sky-survey team on January 3, 2025, it was so dim it was initially misclassified as a faint asteroid. It took subsequent imaging, which revealed a small coma (the gaseous envelope) and a faint tail, to correctly identify and reclassify it as a comet. This initial oversight highlights the subtle nature of these deep-space wanderers. Don't miss this fleeting chance to witness a cosmic event that will not be repeated for over a millennium. As Comet Lemmon sweeps past, it offers a dramatic reminder of the vast, ever-moving, and spectacular universe beyond our planet.

More on Starlust

Comet Lemmon (C/2025 A6) is easily visible in the evening sky this week—here's how to locate it

Will Comet C/2025 A6 (Lemmon) be bright enough to see with the naked eye on October 21?

MORE STORIES

The SLS core stage is currently in a vertical position for integration with the rocket's boosters, which were assembled last week. Here's the latest update about Artemis III.
5 hours ago
After reaching full illumination on October 26, the Moon will pass near the iconic Pleiades cluster.
1 day ago
Long interpreted in symbolic terms, the new study suggests that Vincent van Gogh's 1889 masterpiece came into being through observation of the actual night sky in late July.
3 days ago
Here are some tips for photographing the Orionid meteor shower with a camera as it peaks tonight.
6 days ago
A nearly Full Moon pairs with Saturn in the coming days before attaining the Full Moon, or the Hunter's Moon phase. Here's how to watch the meetup.
7 days ago
After a stunning celestial show by the Draconids in early October, the Orionids will be the second meteor shower visible streaking across the sky.
Oct 19, 2026
Residents of many of the northern U.S. states, from Washington to Maine, could get a chance to see auroras around midnight.
Oct 19, 2026
Follow this set of simple guidelines to capture stunning views of the Full Moon on October 26.
Oct 16, 2026
The Southern Taurids are a complex annual meteor shower that will reach its first peak on the night of October 14, 2026. Here's all you need to know.
Oct 14, 2026
If you've looked up at the sky this month, there's a chance you might have seen at least one of them. If not, this guide has you covered.
Oct 13, 2026