Comet C/2025 A6 (Lemmon), discovered in January by the Mount Lemmon observatory in Arizona, reached its peak brightness on October 21, about 90 million kilometers from Earth. It is visible to the naked eye in dark areas, especially in Brazil, until early November, before moving away from the Sun. The phenomenon coincides with the Orionid meteor shower, creating a double celestial spectacle.
The comet, originating in the Kuiper Belt, reflects sunlight in its coma, forming a greenish tail visible with binoculars or the naked eye.
- Where to observe: Low-light locations, such as rural areas, are ideal.
- Best time: After sunset, from October 27th, close to Mercury, Mars and Antares.
- Equipment: Binoculars or telescopes highlight the tail; to the naked eye, it appears as a fuzzy point.
Optimal observation conditions
The visibility of Comet Lemmon depends on specific conditions. Locations far from urban centers offer the best observation opportunities.
Clear skies and the absence of light pollution are essential to identify the green spot.
Comet trajectory and characteristics
Lemmon has an elongated orbit, typical of long-period comets. It takes about 1,300 years to complete one revolution around the Sun.
Its brightness intensifies as it approaches the Sun, releasing gases such as cyanogen and diatomic carbon.
The tail, formed by the solar wind, always points away from the Sun.
Perihelion, the closest point to the Sun, will be on November 8, when the brightness may increase.
Orionid meteor shower
The passage of Lemmon coincides with the Orionids, caused by fragments of Halley’s Comet. The peak of the rain occurred this week, with dozens of meteors per hour.
“Shooting stars” are visible on clear nights, especially in dark areas.
The eyes need 20 to 30 minutes to adapt to the darkness.
Other comets in 2025
In addition to Lemmon, other comets mark the year. C/2024 G3 (ATLAS) was visible in January, with peak brightness at the beginning of the year.
24P/Schaumasse will be observable between December 2025 and January 2026, requiring telescopes.
210P/Christensen, visible until December, reaches its peak in November.
Tips for Observers
To enjoy the spectacle, astronomers suggest:
- Choose locations with low light pollution.
- Use astronomy apps to locate the comet.
- Take binoculars for details of the tail.
- Observe between sunset and midnight, starting October 27th.
