This October will see a once-in-80,000-year event, when Comet Tsuchinshan-ATLAS passes by Earth. First spotted in 2023, the comet (technically called C/2023 A3), which has been billed the “comet of the century” by some in the astronomy community, could be so bright that it outshines the stars around it in the sky, and even the planets Jupiter and Venus. Just how spectacular the comet is remains to be seen, as it is hard to predict how comets will appear in advance, but the possibility has skywatchers around the world excited for the event.
Whether you are able to see the comet with the naked eye depends on whether it will be as bright as optimists hope. “We’re all really excited about the prospect of the Comet A3 (Tsuchinshan-ATLAS) and how it might just be a nice bright object in the night sky,” said the Royal Astronomical Society’s Robert Massey. “I would think that you’re going to need a pair of binoculars to pick it out, or a telescope if you have the right kind of telescope with a wide field and you know exactly where to look. But who knows, it might be visible to the naked eye as well. We’ll just have to wait and see.”
Comets glow brightly because they are balls of rock and ice, and when they approach the sun that ice begins to sublimate into gas. The ice particles reflects the sun’s light, making them appear to shine, and the gas being given off gives them their signature tail. Comet Tsuchinshan-ATLAS is currently passing by the sun, but it will likely be at its brightest when it passes by Earth in mid-October.
You can start looking out for the comet now by looking to the constellation Sextans, according the Planetary Society, by looking to the east around an hour before sunrise (for those in the Northern Hemisphere). It will get brighter as we approach mid-October, and your best chance to get a good view is to find somewhere away from cities or other sources of bright lights and to look just above the horizon.
If you’re interested in trying to photograph the comet, that should be possible too. “It helps if you’ve got a good DSLR camera and can take a series of exposures — a lot of astrophotographers do so successfully,” Massey said. “Also, if you have a good mobile phone camera and a small telescope, you can hold the mobile phone against the eyepiece of the telescope and try to take a picture that way. That worked well with comets like NEOWISE and it might work well with this one, depending on how bright it is.
“And if it’s genuinely easy to spot, you might, might be able to pick up your mobile phone, rest on something, and just point and shoot.”