If you want to see comet Tsuchinshan-ATLAS (also called C/2023 A3 and Comet A3) and photograph it, this weekend offers your last decent chance.
It’s not as bright as it was, so you’ll need binoculars and patience to see it, particularly from urban areas with light-polluted skies.
“It should stay fairly prominent over the next few days as the fading comet is balanced out by the darker sky as it moves away from the sun until about Oct. 19 and Oct. 20,” said astronomer Dr. Qicheng Zhang of Lowell Observatory in Flagstaff, Arizona, in an email.
Although it has been visible to the naked eye, you’ll now need a pair of binoculars, but the flip side is that it’s now in the sky for much longer than it was earlier in the week, and it is now set against a much darker sky.
So, should you head to somewhere that looks dark on a light pollution map or to a Dark Sky Place? On Sunday, perhaps, but perhaps don’t bother on Friday and Saturday because the moon — only just past full — will rise only a relatively short time after sunset and bleach the night sky. Check a moonrise calculator to see if it works with the intended times you plan to visit.
Here’s exactly where and when to see the comet this weekend.
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.
Where And When To See The Comet On Friday, Oct. 18
Essential information: now just past full, the “Hunter’s Supermoon” will rise about 50 minutes after sunset/moonrise where you are, which is about the same time as the comet becomes visible.
This evening, the comet will due west, 40 degrees from the sun in Serpens, and visible close to the western horizon about 45 minutes after sunset, setting around two hours 25 minutes later. That means it will be in the sky for about 15 minutes longer than on Thursday. The comet will be above a point roughly halfway between Venus and Antares, making a triangle shape. A 96.4%-illuminated waning gibbous moon will rise while you look for the comet.
Where And When To See The Comet On Saturday, Oct. 19
Essential information: the comet has been visible to the naked eye until now, but around Saturday, Oct. 19 or Sunday, Oct. 20, it will fade quickly as it enters the constellation Ophiuchus. Use binoculars!
This evening, the comet will due west, 42 degrees from the sun in Ophiuchus, and visible close to the western horizon about 45 minutes after sunset, setting around two hours 35 minutes later. That means it will be in the sky for about 10 minutes longer than on Friday. The comet will be above a point roughly halfway between Venus and Antares, making a vast triangle shape.
Where And When To See The Comet On Sunday, Oct. 20
Essential information: the comet has been visible to the naked eye until now, but around Saturday, Oct. 19 or Sunday, Oct. 20, it will fade quickly. Use binoculars!
This evening, the comet will due west, 45 degrees from the sun in Ophiuchus, and visible close to the western horizon about 45 minutes after sunset, setting around two hours 45 minutes later. That means it will be in the sky for about 10 minutes longer than on Saturday. Now visible in astronomical darkness, the comet will again be above a point roughly halfway between Venus and Antares, making a vast triangle shape.
What’s Next For Comet Tsuchinshan-ATLAS?
That’s about it for comet Tsuchinshan-ATLAS. It will likely remain visible through binoculars until early November, but it will get dimmer each night and eventually fade from view as it journies back to the outer solar system and the Oort Cloud, a sphere of debris around the solar system where millions of comets reside.
Wishing you clear skies and wide eyes.
