See the surprise comet C/2025 A6 (Lemmon) now! The long-period comet is brighter than expected, offering a rare naked-eye view before it disappears for over 1,000 years. Best viewing dates and tips inside.

Sky-gazers across the Northern Hemisphere are currently being treated to an unexpected celestial visitor: Comet C/2025 A6 (Lemmon). Initially predicted to be a faint, binocular-only object, the comet has dramatically exceeded expectations and is now performing as one of the most exciting cometary events of 2025.

Discovered on January 3, 2025, by the Mount Lemmon Survey in Arizona, the comet was initially expected to peak at a modest magnitude of around +10.

However, after emerging from solar conjunction in mid-August, the long-period comet showed a remarkable increase in brightness, suggesting a significant outburst of activity on its icy nucleus.

Closest Approach and Peak Brightness

Comet C/2025 A6 (Lemmon) made its closest approach to Earth (perigee) just yesterday, on October 21, 2025, passing at a distance of approximately 0.60 AU (about 90 million kilometers).

Coincidentally, this peak viewing opportunity arrived on the night of the New Moon, maximizing the visibility for observers under dark skies.

The comet is now heading toward its closest approach to the Sun (perihelion) on November 8, 2025, at a distance of 0.53 AU.

Current observations and optimistic predictions indicate it could reach an apparent magnitude as bright as +3.5 to +4.5 by the end of the month, making it potentially visible to the naked eye from locations free of significant light pollution.

Where and When to Look

For Northern Hemisphere observers, the comet is currently a brilliant target in the evening sky.

Current Location: As of October 22, 2025, Comet Lemmon is transiting the constellation of Boötes.
Best Viewing Period: The most favourable viewing window is from mid-October through early November. The comet is best seen in the evening sky shortly after sunset, positioned in the west to northwest sky.
Finding the Comet: Look for the bright star Arcturus in Boötes. Around its closest approach, the comet was visible near Arcturus, offering a stunning low-power binocular view with both objects in the same field of view.

While current magnitudes already make it an easy target for binoculars, its extended, fuzzy appearance means it will look like a faint, slightly blurry smudge to the unaided eye—if conditions are dark enough.

Binoculars or a small telescope are highly recommended for the best view of its bright coma and evolving tail features, which have shown knots and disconnection events as it interacts with the solar wind.

A Once-in-a-Millennium Visitor

Comet C/2025 A6 (Lemmon) is a long-period comet, meaning its current visit is a rare event. Scientists estimate its inbound orbital period at about 1,350 years.

After its swing around the Sun in November, the Sun’s gravity will slightly alter its path, reducing its outbound orbit to approximately 1,150 years.

Regardless, this means the comet will not return to the inner solar system until roughly the year 3175.

For a brief period in October and November 2025, stargazers have the chance to witness a spectacular traveler from the outer reaches of the solar system, a reminder of the dynamic and unpredictable nature of these icy visitors.

Be sure to look skyward—you won’t get another chance for over a thousand years!