The luminous comet Lemmon visible in the sky to the naked eye, when and how to observe it?

The new comet Lemmon is shaping up to be the astronomical event of the autumn! If last year's Comet of the Century is not about to resurface, it's C/2025 A6, christened Lemmon, which is the center of attention. If all goes well, it should become visible to the naked eye in just a few weeks, and already is if you have binoculars. Watched since January 2025, when it was discovered by the Mount Lemmon Survey telescope in the USA, the comet is about to appear.

• To be read
• This week's top picks in Paris and Île-de-France, April 6–12, 2026.

When can you see Comet Lemmon?

Currently at magnitude 6, Lemmon should approach magnitude 3 by the end of October, becoming more visible in the sky. You can already try your luck from the middle of the month, around October 10-15, before it gets brighter in the last ten or so, around October 21, 2025, at the very start of the night around 9pm. As for where to look for it through the stars, look under the constellation of the Big Dipper, at a height of 15° above the horizon, equivalent to the height of a fist with the thumb raised.

How to observe the comet in Paris and the Ile-de-France region?

Of course, you'll have to hope for good weather, with clear, cloudless skies, to make the most of it. As usual, avoid visual pollution and stay as far away from big cities as possible. Fortunately, the Moon will be on our side this time, as it's full at the very beginning of the month. You can also download an application like Star Walk to find it more easily.

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What about the other comets of the moment?

This comet is considered ancient, having passed close to the sun several times. Other interesting comets to look out for this autumn include K1 Atlas, visible in the morning, but likely to pass close to the Sun and disintegrate. Another more likely is R2 Swan, with its long tail, observable with binoculars for the moment, and which could become so with the naked eye around October 20, in the constellation Libra.

Happy comet watching to come!