It was very early in the morning In January 2025 when a favorable location is seen at Mt. Lemmon visible in Arizona. Subsequent observations revealed that the object was traveling to the outer edges of the solar system, and was named Comet Lemmon (C / 2025 A6). Its “period” – the time it takes to complete its long solar cycle – is about 1,350 years.
At first, the comet was so faint that it could only be seen with special equipment. But it blossomed as quickly as the months passed, and when fall came, it was bright enough to be observed with binoculars. Now it will bloom even now, as it is close to both the Earth and the Sun, and can be seen with the naked eye.
According to Nasa, Comet Lemmon will make its closest approach to Earth on October 21, 2025, passing at a distance of 0.60 stellar units, or AU (1 AU distance between Earth and the Sun). The comet is predicted to reach Perihelion – the point at which it is closest to the Sun – on November 8
The comet’s tail will also be at its longest extension near Perihelion. Tails form on comets when the sun’s rays heat the ice and frozen gases, causing them to be ejected from the gas in the comet strale streak. The stronger the radiation, the larger the size of this effect, and therefore the tails of comets grow as they approach the stars and retract again as they depart.
Comet Lemmon is notable for its green tint. This is caused by a cloud of gas that surrounds the nucleus of the comet, known as “coma,” with the color formed by diatomic carbon (molecules of two carbon atoms) interacting with the sun.
How to view the Comet
Since the beginning of October, Comet Lemmon can be found slightly below the handle in the big dipper (or plane, as it is known in the UK), which is part of the larger URSA organization. If you look at the northern sky, you will be able to track its path. In the northern hemisphere, it is predicted to appear in the northwest-to-west sky after sunset from mid-October onwards. It will be low above the horizon and is expected to emit a faint glow just after sunset.
The best time to see the comet is about a week before and after its closest approach. In November, the Comet will cross the celestial equator and be visible from the Southern Hemisphere.
Binoculars or small telescopes are better to see, but if you choose a place with little light pollution, you can catch it with the naked eye. If you look at the sky just after sunset when the light is low, you can see it. Struggling to find a comet, use the Star Map app on your smartphone or Planetarium Software to help you pinpoint its location.
