Two Comets Are on Their Way to Our Skies in October—Here’s How to See Them

Already 2024 has been a banner year for skywatchers, having offered North America a total eclipse and a spectacular display of the northern lights (with the possibility of more to come). And as if that’s not enough for one year, October may well bring us a pair of comets as a finale.

It’s tempting to call these apparitions once-in-a-lifetime events, but that’s actually underselling them both significantly. The first comet to arrive, called Tsuchinshan-ATLAS, only visits once every 80,000 years. And snappily-named Comet C/2024 S1 ATLAS is classified as a non-periodic comet—meaning it may never come back this way again.

So these are not “maybe next year” sights. This show will not have a return engagement; you’ll have to catch it this time. Here’s how:

Act 1: Tsuchinshan-ATLAS

Photo courtesy of NASA

First up is Comet Tsuchinshan-ATLAS. It will be too close to the sun to safely view for the next few days, but by October 11, it should be possible to see it very low in the West just after sunset.

Each evening after October 11, the comet will be slightly higher in the sky at dusk than it was the night before—but also a little dimmer. It’s hard to say which night will find the comet in that sweet spot of peak visibility, so try to observe it every evening you can. Look west-southwest, just after sunset. The customizable online chart here may come in handy to help you find it.

To spot the comet, seek out an open space with low light pollution, and, crucially, a low western horizon. Tsuchinshan-ATLAS is expected to be a naked-eye object, but early in the evening, binoculars may help you pick out the comet against the still-bright sky. Try taking photographs, too, using a long exposure, and ideally a tripod. You may find that photos capture more details of the tail (or tails!) that the comet is expected to develop.

What will it look like? On October 11, Tsuchinshan-ATLAS will be about as bright as Sirius, the brightest star in the night sky. By the 17^th, it will look more like fairly ordinary Polaris (the North Star) and by October 22, it will be near the limit of what the naked eye can see in urban or even suburban areas—or so go the predictions of scientists studying Tsuchinshan-ATLAS. The fact is that astronomers can predict when comets will enter our solar system, and on which days they’ll be closest to Earth. But brightness depends on many variables, and as anyone old enough to remember the underwhelming appearance of Halley’s Comet in 1986 can tell you, they don’t always live up to their hype.

Comets are like cats: They have tails, and they do precisely what they want.

David H. Levy, Comets: Creators and Destroyers

Act II: Comet C/2024 S1 ATLAS

View this post on Instagram

A post shared by Ethan Chappel (@chappelastro)

C/2024 S1 ATLAS may not be much to look at yet—it’s the fuzzy dot at the center of the photo—but it’s expected to be a naked-eye object by late October.

That said, if Tsuchinshan-ATLAS is a bust, or if the weather doesn’t cooperate for you, you may get a remarkable second chance at a comet toward the end of October. Comet C/2024 S1 ATLAS  isn’t as much of a sure thing—its odds of surviving its close brush with the sun later this month are not 100%. But if it does come through intact, it may be even brighter than Tsuchinshan-ATLAS—brighter, even, than the planet Venus, which would make it the brightest object in the night sky other than the moon.

Comet C/2024 S1 ATLAS probably won’t be quite that bright by the time it’s visible in the West. That’s because this comet’s trajectory puts it on a path where it’s best visible in the early morning in the Southern Hemisphere. By the time we can see it in North America, it will be on its way out of the solar system and getting dimmer by the day.

To get a glimpse of it, start looking low in the western sky immediately after sunset on or after October 28. Like Tsuchinshan-ATLAS, Comet C/2024 S1 ATLAS will be at its brightest when it is low and easily overpowered by the twilight horizon’s lasting brightness. It, too, will appear higher in the sky every evening while getting progressively dimmer. As with the previous comet, try using binoculars, which may help you spot the comet as well as pick up detail in its magnificent tail. TheSkyLive has a tracker for this object, too.

How did we get so lucky as to have two once-in-a-lifetime comets swing by in the same month? That’s just the luck of the cosmic draw. Will we be lucky enough that they both put on a star-making performance? Only time will tell. Happy observing!

Encore: A New Star, and a Meteor Shower

Photo by Austin Human on Unsplash

Tsuchinshan-ATLAS and C/2024 S1 ATLAS will not be making another appearance any time soon, but the big stellar sights are not done for the year. Scientists have their eyes on another unpredictable, one might say diva-like object: a star in the constellation Corona Borealis, which is expected to dramatically blow off a layer of itself any day now. (It’s actually a bit overdue; scientists expected this event to take place no later than September, but T Coronae Borealis will take the stage when she’s good and ready. Read more here.)

More reliably, we can count on the annual Orionid meteor shower on the night of October 20-21. This shower will probably produce only a modest number of shooting stars per hour, but Orionids are known for being bright and long-lasting, and are worth enduring an extra-sleepy Monday for. (We’ve got the scoop here.)

Fun fact: Meteor showers are usually caused by cosmic debris trails that comets make during their passage through our solar system. This is true of the Orionids, and this shower’s parent comet is none other than Halley’s Comet, which may have been a bit of a dud during its last pass, but does pay this exciting dividend every October.

We only recommend things we love. If you buy something through our site, we might earn a commission.