{"id":798509,"date":"2025-09-30T12:35:29","date_gmt":"2025-09-30T17:35:29","guid":{"rendered":"https:\/\/spaceweekly.com\/?p=798509"},"modified":"2025-09-30T12:35:29","modified_gmt":"2025-09-30T17:35:29","slug":"comet-lemmon-might-be-the-best-comet-of-2025","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=798509","title":{"rendered":"Comet Lemmon might be the best comet of 2025"},"content":{"rendered":"


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View at EarthSky Community Photos. | John Chumack in Yellow Springs, Ohio, captured Comet Lemmon (C\/2025 A6) along with some satellite trails on September 27, 2025. John wrote: \u201cEarly Saturday morning I had to wait an hour longer just for it to clear the trees in the northeast. I was finally able to image it around 6:00 a.m., with dawn rising fast, and the satellite traffic was crazy.\u201d Thank you, John!<\/figcaption><\/figure>\n

Comet Lemmon might be the best comet of 2025<\/h3>\n

Of all the comets suddenly soaring into our skies, Comet Lemmon (C\/2025 A6) might be the best of the year. And this comet favors Northern Hemisphere observers. In early October, Comet Lemmon will cut a path underneath the giant ladle shape of the Big Dipper in Ursa Major. The comet will be closest to Earth on October 21, 2025, but it will continue to brighten after that, likely reaching its brightest \u2013 and possibly visible with your eyes alone \u2013 around October 31 or November 1. Comet Lemmon reaches its closest point to the sun on November 8.<\/p>\n

\"Starfield
View at EarthSky Community Photos. | Tameem Altameemi in the United Arab Emirates captured Comet Lemmon on September 19, 2025. Tameem wrote: \u201cThis non-periodic comet is currently shining at magnitude +8, making it a fine telescopic target. In the image, you can see the bright nucleus at the core, the surrounding coma of gas and dust, and a faint dust tail stretching away from the sun. Unlike periodic comets that return on a regular cycle, C\/2025 A6 follows a very elongated orbit and may not return for thousands of years, if ever.\u201d Thank you, Tameem!<\/figcaption><\/figure>\n

How to see Comet Lemmon<\/h3>\n

Comet Lemmon favors Northern Hemisphere viewers, spending much of October near the Big Dipper. But on northern fall evenings, the Big Dipper is quite low on the horizon. So during the first half of October, if you want to catch a glimpse of it, you\u2019ll likely have to look in the early hours of the morning until before sunrise. And during the first half of the month, expect the comet to still be dim, around magnitude 7, and only visible with optical aid.<\/p>\n

By mid-October, the comet will become easier to see, rising in the evening sky. On October 16, 2025, Comet Lemmon will be passing near Cor Caroli, the brightest star in Canes Venatici the Hunting Dogs. At this point, some estimates put the comet at a possible unaided eye visibility and still brightening.<\/p>\n

Comet Lemmon will be at its brightest at the end of October and beginning of November. Estimates of its brightness range from magnitude 4 to 2.5. Keep in mind, comets are notoriously unpredictable. But there\u2019s a good chance you might be able to find the comet with your eyes alone from a dark-sky site.<\/p>\n

On Halloween and into early November, Comet Lemmon will pass in front of the stars of Ophiuchus. See the finder charts below.<\/p>\n

Finder charts for Comet Lemmon<\/h3>\n

The good news is that during closest approach in mid-October, Comet Lemmon is in the sunset sky. Find a good observing site with no obstructions to the western horizon so you can observe and photograph this \u201conce in a lifetime\u201d comet. Our finder charts are for the Northern Hemisphere. To get a precise chart for your location, visit Stellarium-Web.<\/p>\n

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Finder chart for Comet C\/2025 A6 Lemmon on October 11, 2025. Look northeast before sunrise. Image via Eddie Irizarry\/ Stellarium.<\/figcaption><\/figure>\n
\"Star
Finder chart for Comet C\/2025 A6 Lemmon on October 20, 2025. Look northwest after sunset. Image via Eddie Irizarry\/ Stellarium.<\/figcaption><\/figure>\n
\"Star
Finder chart for Comet C\/2025 A6 Lemmon on October 21, 2025. Look northwest toward the bright star Arcturus in Bo\u00f6tes. Image via Eddie Irizarry\/ Stellarium.<\/figcaption><\/figure>\n

Additional finder chart<\/h3>\n
\"Finder
Finder chart for Comet Lemmon (C\/2025 A6) looking about 2 hours before sunrise, Face northeast and use binoculars. Image via Bob King (Astro Bob). Used with permission.<\/figcaption><\/figure>\n

History of Comet C\/2025 A6 Lemmon<\/h3>\n

Astronomers using the 60-inch (1.5-meter) telescope at Mt. Lemmon, Arizona, discovered this comet back on January 3, 2025. There are also precovery images of the comet in PanSTARRS data from as early as November 12, 2024. The term precovery<\/em> is one that astronomers use to mean pre-discovery recovery. So the comet was on images earlier than those in which it was discovered. But they did not realize it was there until they went back and looked for it. Using this extended data, astronomers have been able to calculate its orbit. And it has an orbit that takes it about 1,350 years to circle the sun once. <\/p>\n

\"A
View at EarthSky Community Photos. | David Hoskin in Halifax, Nova Scotia, Canada, captured Comet A6 Lemmon on September 29, 2025. David wrote: \u201cThe comet continues to brighten and may, from a dark site, become visible to the unaided eye by late October.\u201d Thank you, David!<\/figcaption><\/figure>\n

Other comets currently active<\/h3>\n

Comet Lemmon is just one of a number of comets currently in our sky. The most famous is probably the interstellar comet, 3I\/ATLAS, which will pass closest to the sun in late October. It\u2019s been brightening more quickly than expected, but at the moment it is still well out of range of visibility with the unaided eye.<\/p>\n

Another comet that recently came upon the scene is Comet SWAN. As of the beginning of October, it might be breaking into range of the unaided eye from a dark-sky site.<\/p>\n

Bottom line: Comet Lemmon might be the brightest comet of 2025. It could become bright enough to see with your eye alone in late October and early November.<\/p>\n

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Kelly Kizer Whitt<\/h4>\n

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About the Author:<\/h6>\n

Kelly Kizer Whitt – EarthSky\u2019s nature and travel vlogger on YouTube – writes and edits some of the most fascinating stories at EarthSky.org. She’s been writing about science, with a focus on astronomy, for decades. She began her career at Astronomy Magazine and made regular contributions to other outlets, including AstronomyToday and the Sierra Club. She has nine published books, including a children’s picture book, Solar System Forecast, and a young adult dystopian novel, A Different Sky.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n