The A3 comet will soon be visible in the night sky, but the clock is ticking on its ideal viewing time.
Known officially as Comet Tsuchinshan-ATLAS, the celestial object reached a state known as its “perihelion” on Sept. 27, meaning the point at which it’s closest to the sun. It’ll reach the point closest to Earth in mid-October, and until then, eager stargazers will have a few opportunities to try to get a look at it.
Comet A3 has been on the radar of astronomers since its discovery early last year and has built up a significant amount of hype since then. In a press release from the Search for Extraterrestrial Intelligence Institute, aka SETI, Franck Marchis, director of citizen science at the institute, said A3 could become one of the brightest visible objects in the Northern Hemisphere’s sky. Marchis also said A3 will be “as unpredictable as it is magnificent” and potentially “one of the most significant celestial events of the year or even the decade.”
For more, read about the discovery of water on one passing comet and about why some have called A3 a contender for “comet of the century.”
What is Comet A3?
Comet Tsuchinshan-ATLAS is a celestial body originating from the Oort Cloud, a massive shell of objects that encircles the solar system.
It was first discovered in January 2023 and was named after the two observatories that spotted it in the sky, independent of each other. Scientists reckon the celestial traveler makes its way through our solar system every 80,000 years, leading Phys.org to note that the last time it passed by would’ve been when Neanderthals were still kicking around.
When will be the best time to see Comet A3?
Based on currently available info, Comet A3 will be the most visible in the wee morning hours on Thursday, Oct. 3. It’s estimated it’ll be viewable between 75 and 60 minutes before sunrise wherever you’re trying to observe it, to the east-southeast and 18.2 degrees from the sun.
A word of caution for the overeager, as early observers have suggested A3 might not yet be visible to the naked eye, necessitating specialized viewing equipment.
Will it be visible any other times?
Comet A3 will reappear just before sunrise this weekend, Oct. 4 to 6, though at this stage the glare from the rising sun is expected to make it much harder to spot.
A3 will also become visible in the twilight hours just after sunset later in the month, around Oct. 12, with that specific date being the point at which the comet will be the brightest during this phase. Observers should look west immediately after sunset during this time to try to catch a glimpse.
For more, check out the dazzling photos astronauts have snapped of Comet A3.
