Want to see the comet tonight? If you’ve seen the hype online about Comet Tsuchinshan-ATLAS (also called C/2023 A3 and Comet A3), you’ll want to know exactly when to look, where it is and how to find it.
After all, the rare sight of a naked-eye comet — one that orbits the sun only once every 80,000 years — is a rival sight to Thursday’s global display of Northern Lights.
Luckily, it’s now easily visible in the west in the post-sunset sky, if you have clear weather. As an extra bonus tonight, on Thursday, Oct. 17, it will be possible not only to see the comet, but — right behind you — a rising “supermoon.”
The comet is now just slightly past its absolute brightest, but in some ways that’s a good thing because it’s now much higher in the sky. That means you can watch from anywhere — no special trips to mountainsides and beaches required — and it’s now shining in a darker sky that it was a few days ago. If you find it, here’s how to photograph it.
It’s now almost 50 million miles distant, but crucially, it’s higher in the sky, so easier to see above mountains and buildings.
Here’s exactly when and where you need to look to see the comet with your naked eyes on Thursday, Oct. 17.
Note: times and viewing instructions are for observers at mid-latitudes in the Northern Hemisphere. Check the exact time of sunset where you are and the comet’s setting times on Stellarium Web for times accurate for your exact location.
How To Locate Comet Tsuchinshan-ATLAS: Thursday, Oct. 17
Position: west, 37 degrees from the sun in Serpens
Time: 45 minutes after sunset where you are
Magnitude: +1.3
Comet’s distance from the sun: 60.9 million miles (98 million kilometers)
Comet’s distance from Earth: 49.9 million miles (80.3 million kilometers)
This evening, the comet will be visible above the western horizon about 45 minutes after sunset, setting around two hours 10 minutes later. That means it will be in the sky for about 15 minutes longer than on Wednesday.
However, there’s a good reason to get outside 10 minutes before sunset in the west — so about an hour before the sky darkens enough for the comet to appear — because the full “Hunter’s Moon,” a big, bright supermoon — will rise in the east.
How To Use A ‘Cosmic Coat-Hanger’ To Find The Comet
Its brightness will bleach the sky, but not enough to make the comet hard to see. Swivel 180 degrees back from the moon to look west for the bright planet Venus and the bright twinkling, reddish star star Arcturus, the brightest star in the constellation Boötes; the comet will be high above a point roughly halfway between them.
Think of it this way; if Arcturus and Venus are the ends of a coat-hanger, the comet is the hook. With this knowledge you should be able to find the comet with your naked eyes, but since you’ll be outside during twilight and there will be a lot of moonlight, take any pair of binoculars to speed-up the process.
As a bonus, when you do locate comet Tsuchinshan-ATLAS, a pair of binoculars will give you a great view.
How Do You Pronounce ‘Tsuchinshan?’
Tsuchinshan is the English name for the Purple Mountain Observatory in Nanjing, China, which discovered comet Tsuchinshan-ATLAS in January 2023. That observatory is also commonly called Zijinshan. The pronunciation is similar to “tsu-jing-shon.”
“The tsu part actually sounds fairly close to the ts sound in English like in itsy bitsy,” said astronomer Dr. Qicheng Zhang of Lowell Observatory in Flagstaff, Arizona, who has been monitoring the comet, in an email. “The chin part — now usually transliterated as jin — sounds quite the jin in jingle bells,” and the shan sounds sort of like sun, but with the un part sounding perhaps a bit more like the on sound in von with a German accent.”
Now you can say it, and see it, you’re sorted.
Check my feed every day this week and next for a daily “comet tracker” with sky-charts and tips for viewing the comet.
Wishing you clear skies and wide eyes.
