Comet Tsuchinshan–ATLAS photographed from Indonesia in late September 2024. (David Davies / iStock)

Move over Northern Lights, Comet Tsuchinshan–ATLAS has entered the picture.

Scientists have been tracking the orbit of Tsuchinshan–ATLAS for nearly two years, waiting to see if the giant ball of space ice would survive its close encounter with the sun.

It did.

Tsuchinshan–ATLAS (named for the pair of observatories that independently discovered the comet in 2023) is burning as bright as Polaris, the North Star, with an intact comet head — known as a “coma” — that measures more than 100,000 miles in diameter and a tail stretching for nearly 20 million miles. 

Now the comet is showing up in the night sky over Chicago, where in the coming days it might even be visible to the naked eye.

Michelle Nichols, director of public observing at Adler Planetarium, knows Chicagoans are skeptical about being able to see space phenomena, having been burned plenty of times by light pollution.

“It’s living up to the hype,” Nichols said of the comet’s brightness. 

Tsuchinshan–ATLAS photographed by astronauts on board the International Space Station. (Credit: ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center)

Joe Guzman, aka the Chicago Astronomer, reported a Tsuchinshan–ATLAS sighting from the 606 Bloomingdale Trail on Sunday night, before 7:30 p.m.

“The nucleus was quite bright and tail longer than I expected,” Guzman shared on his website. 

Tsuchinshan–ATLAS has already been thrilling sky watchers in the southern hemisphere for weeks, but only recently became evident in the northern hemisphere. It’s gradually been rising in the sky after sunset, making it easier to spot.

The best viewing will occur between now and Oct. 26, as Tsuchinshan–ATLAS climbs higher, later at night, though it will also grow dimmer as it travels away from Earth. 

Here’s how to catch a once-in-a-lifetime glimpse of this visitor from the outer edge of our solar system.  

Viewing Events

If you don’t trust your own ability to locate the comet, let the professionals be your guide. 

— Oct. 17: Guzman will post up with his telescope for public sessions at the 606 Bloomingdale Trail, 6:30-8:30 p.m.; meet at the west end of the trail, 1805 N. Ridgeway Avenue. (Oct. 17 is a make-up date for a session canceled on Monday, due to cloud cover.)

— Oct. 16 and Oct. 23: The Adler Planetarium will host outdoor sessions on the west side of the building, beginning at 6:45 p.m., running until 8 p.m. on the 16th and until 9 p.m. on the 23rd. The planetarium will be pulling out its smaller telescopes and binoculars rather than using its observatory scope, Nichols said.

Sessions are weather dependent, so check social media for updates before heading out the door: Guzman on X/Twitter and Facebook; 'Scopes With the Adler on Facebook.

Where To Look

Find a place with unobstructed views to the west/southwest, and scan the horizon after sunset. Experts stress it’s important not to look for the comet through an unfiltered lens until the sun has fully set, otherwise there’s a strong risk of eye damage.

Dark skies will be helpful later in the month, but as noted above, Guzman was able to spot the comet from a vantage point in Chicago.

“I have associates who have used the tops of elevated parking facilities looking west,” Guzman told WTTW News via email. “A view from a tall building/rooftop would be interesting and doable too.”

Use Venus as a marker, and reference this handy chart from the Adler. It will be helpful to use binoculars to locate the comet, but it could then be visible without aid once you've fixed on it.

(Courtesy Adler Planetarium)

What To Look For

When he saw it Sunday, the comet was a naked-eye object, "Even under glaring city lights at the 606," Guzman said.

By the end of the week, though, the comet as a whole, with its signature tail, will likely have fallen out of the naked-eye range. “But the coma/head should still be visible as a fuzzy star," he said.

Regardless of whether it's viewed with the eye, binoculars or a telescope, Tsuchinshan–ATLAS won't be streaking across the sky — that's not how comets appear, Guzman said: “If the object moves while you are watching ... it’s an aircraft.”

This article originally published Oct. 14 and has been updated with new information.

Contact Patty Wetli: @pattywetli | (773) 509-5623 |  [email protected]