How to see comet Tsuchinshan-ATLAS in Minnesota before it's gone

Comet Tsuchinshan-ATLAS was only discovered last year and already we’re facing the last time in our lives we’ll be able to see it — it only comes around every 80,000 years.  

Telescopes have been following this comet for the past year and, in their latest research, they have learned its orbital path is headed straight out our solar system.  

“So if you do not see it here, in the next couple weeks, it is gone,” said Thaddeus LaCoursiere, Planetarium Production Coordinator at the Bell Museum. “It is headed out of the solar system, so once-in-a-lifetime event, once-in-our-solar-system’s-lifetime event.” 

Comets are named after whoever discovered them. With the advent of telescopes and automated sky surveys, comets are now named after those, too. In this case, it was found by the Purple Mountain — or Tsuchinshan — Observatory in China, and then the Atlas South Africa telescope confirmed the discovery. 

The comet’s full name is C/2023 A3 Tsuchinshan-ATLAS, which is a blend of both.  

Studying the comet revealed that it came from the Oort Cloud, a distant realm that is jammed with billions of icy planetesimals, most of which are remains from the formation of the solar system.  

How long is the comet visible in the night sky?  

This week it will be visible until around 9 p.m. As we near the end of October, it will be visible until around 10 p.m., but it will be fainter as we get closer to November.  

“I would say it's been dimming a bit as the weeks have gone on. So it is rapidly approaching the end, and this is really your good last week and last couple weeks to see it,” LaCoursiere said.  

When and where is best to see it?  

Go out about 90 minutes after sunset, which in Minnesota in mid-October is around 7:30 p.m.   

Focus your attention west and about 30 degrees above the horizon.  

LaCoursiere said you can figure that angle out by holding your arms out in front of you, clenching your fists and stacking three fists on top of each other.  

What are you looking for?  

Well, the C/2023 A3 Tsuchinshan-ATLAS comet, of course! But in case you have never seen it before, it looks like a “very faint smudge.”  

It may be a bit difficult to find it in the Twin Cities metro area due to light pollution.

“Look for something that just looks kind of like a little bit of chalk on the chalkboard that's been wiped off, with a little bit of a brighter core, the nucleus,” LaCoursiere said.  

Binoculars may help you find it. LaCoursiere said even a cell phone camera, taking photos with a 5- or 10-second exposure in night mode, can bring the comet out in the night sky. Just be sure to keep the camera still.

Outside of the cities will give you a better chance to view it, even just a 30- or 45-minute drive out of the metro.

Places to catch the comet  

A beginner’s observing session will be held Saturday, Oct. 19, from 5:30 to 11 p.m. at the Lucy Winton Bell Athletic Fields of the Belwin Conservency. This free event is in Lakeland, east of the Twin Cities, and open to anyone who wants to learn and will give attendees a chance to see comet Tsuchinshan-ATLAS.

The Bell Museum in St. Paul is hosting an October Star Party on Oct. 25 from 7:30 to 9 p.m. to celebrate viewing the night sky. They will have telescopes set up outside with hands-on experiences inside. There will also be a planetarium show of Reading the Night Sky hosted by their expert astronomy team. Showtimes are at 7:40, 8:10 and 8:40 p.m. This free event is welcome to all ages.