Have you seen Comet Tsuchinshan-ATLAS yet? If you want to see something to rival Thursday’s global display of Northern Lights (or if you missed the entire show), the sight of a naked-eye comet in the post-sunset sky is unmissable.
Comet Tsuchinshan-ATLAS, also called C/2023 A3 and Comet A3, has now exited the sun’s glare, having yesterday reached its closest to Earth, passing about 44 million miles (71 million kilometers) away. It’s now rising into the night sky immediately after sunset.
Where Is Comet Tsuchinshan-ATLAS?
Tonight, Sunday, Oct. 13, is the ideal time to look for it from the northern hemisphere, but it won’t be a particularly easy sight, at least for now. That’s because it’s currently close to the horizon. Although it’s close to its intrinsic brightest right now, it’s only in the sky for. short time after sunset, so observers are fighting against the fading twilight.
Luckily, it’s racing away from the sun, and is some five degrees farther from our star than it was yesterday. That trend will continue, with it becoming visible farther into the night sky. That means it will be both be observable against a dark sky and remain visible for a longer period after sunset.
However, to see comet Tsuchinshan-ATLAS shortly after sunset tonight you’ll need a clear view of the western horizon — and some patience.
Here’s exactly when and where you need to look to see the comet with your naked eyes on Sunday, Oct. 13.
How To Locate Comet Tsuchinshan-ATLAS: Sunday, Oct. 13:
Position: west, 21 degrees from the sun in Virgo
Time: 45 minutes after sunset where you are
Magnitude: +0.5
Comet’s distance from the sun: 53.9 million miles (86.8 million kilometers)
Comet’s distance from Earth: 44.3 million miles (71.3 million kilometers)
This evening, the comet will be visible close to the western horizon about 45 minutes after sunset. The waxing gibbous moon will be bright, 83%-lit, but that will make no difference since you’ll be viewing the comet in a fairly brightly-lit region of the sky — just above where the sun will have recently set.
Finding the comet against a less-than-dark sky could be a challenge tonight, but you can use the stars and planets to help you. If you have a completely clear sky at the horizon, locate the bright planet Venus in the south-west and the bright star Arcturus in the west. Both will be close to the horizon. Comet Tsuchinshan-ATLAS will be just below a point roughly halfway between them.
Best Time To See Comet Tsuchinshan-ATLAS
This weekend is one of the best times to see the comet. Compared to Friday and Saturday nights, the comet will be a little higher and easier to find, and it will remain in view until a little later in twilight, according to Sky & Telescope. However, the observing window will be very short because comet Tsuchinshan-ATLAS will sink below the horizon soon after it becomes visible.
You will likely be able to see the comet with your naked eyes, but a pair of binoculars will give you a great view.
When To See Comet Tsuchinshan-ATLAS Next Week
“The comet will appear higher in the sky and become easier to spot through the weekend,” states Sky & Telescope, in a press release. “By early next week, it will be at its best for viewing.”
There are reasons to believe that the best nights to see comet Tsuchinshan-ATLAS are ahead of us. From the roughly 10 nights that it should be visible to the naked eye, Monday, Oct. 14, and Tuesday, Oct. 15, are likely to offer the best views simply because the comet will be set against a darker sky. Check back on my page for dedicated viewing guides for both of those evenings.
However, it’s best to grab a view as soon as you can because comets are unpredictable and so is weather; a few nights of cloud could render the comet invisible to you.
What Is Comet Tsuchinshan-ATLAS?
Comet C/2023 A3 (Tsuchinshan-ATLAS) is also a long-period comet from the Oort Cloud — a sphere of comets around our solar system — that returns to the inner solar system only once every 80,000 years.
It was discovered in January 2023 by astronomers at China’s Tsuchinshan Observatory and then re-found the following month by astronomers at South Africa’s Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope.
Check my feed every day this week and next for a daily “comet tracker” with sky-charts and tips for viewing Comet A3.
Wishing you clear skies and wide eyes.
