Comet Tsuchinshan-ATLAS: The Comet of The Year is Here

2024’s best comet is nearing Earth and getting brighter. Here’s how to see it.

A rare comet is lighting up the skies this October. It’s a once-in-a-lifetime chance to witness it, and it might even be visible to the naked eye. 

Comet Tsuchinshan-ATLAS, also known as Comet A3, is a dusty, icy object from the Oort Cloud, with an orbit around the sun that takes about 80,000 years to complete. This means that some of the last people to see it were Neanderthals. 

This is the best opportunity in years, possibly even in a decade, to spot a bright comet. Dan Bartlett, an astrophotographer who tracks comets, said experts were hopeful that Comet A3 would be “highly memorable” and “a real crowd-pleaser.” However, preparation is key.

“It’s just hard to make the time to be in the right place, to have the right experience,” Teddy Kareta, a planetary scientist who specializes in comets at the Lowell Observatory, said.  But Kareta mentioned that after speaking with people who had seen a truly spectacular comet, it was evident that “there’s just nothing like it.”

Here’s all the information you need to be in the right place at the right time to catch a glimpse of the comet.

How bright is Comet A3?

No one can say for sure how bright Comet A3 will be, but Kareta said it had the potential to be the brightest comet seen in a decade.

The last major comet was Neowise in 2020. It was visible to the naked eye and produced stunning photos, such as this one:

Comet Tsuchinshan-ATLAS: The Comet of The Year is Here
Comet Neowise streaking past an Orthodox church in Belarus. Sergei Grits/AP Photo

Astronomers are divided on whether Comet A3 will be as bright as Neowise. 

In recent weeks, A3 has sometimes been brighter than predicted, and at other times, it has matched expectations, according to the BBC’s Sky at Night Magazine and Robert Massey, deputy executive director of the Royal Astronomical Society. Bartlett said that from a dark-sky vantage point at Mono Lake, California — nestled in the Sierra Nevada — he was already able to see the comet with binoculars.

But comets can change quickly, sometimes in just hours. Their brightness depends on the type and amount of gas or dust they emit, which can change suddenly.

Comet Tsuchinshan-ATLAS: The Comet of The Year is Here
This spectacular close-up of Comet Tsuchinshan-ATLAS was made on Sept. 30th from Namibia with an ASA 12″ f/3.6 Astrograph. The comet exhibits a prominent dust tail, a blue gas tail, and what appears to be the beginnings of an anti-tail (at top).
Credit: Gerald Rhemann, Michael Jäger & Denis Möller

For example, in 2007, Comet Holmes suddenly became 500,000 times brighter in just two days because a gas pocket breached its surface, according to Space.com.

“Sometimes people will say that predicting comets is kind of like playing the lottery,” Kareta said.

When and where to see Comet A3

If weather permits, everyone in the Northern Hemisphere should be able to see Comet A3 in October. 

There are two windows for viewing: one was until October 2 and another from October 12 to 30, according to a press release from Massey. 

According to Space.com, during the first window, the comet appeared above the eastern horizon for a 15-minute window starting an hour before sunrise.

The second window, when the comet will be closest to Earth, offers the best viewing opportunity. After sunset, it will shine in the west, just to the left of the Big Dipper’s handle, making it easier to see at a more convenient time.

Comet Tsuchinshan-ATLAS: The Comet of The Year is Here
This simulation anticipates two apparition highlights — the growth of an approximately15° dust tail and even longer gas tail from September 28th through October 2nd. When C/2023 A3 climbs away from the Sun in the evening sky, its dust tail will stretch at least 20°, with an even longer gas tail. Viewing circumstances at dusk are also ideal for viewing the comet’s anti-tail, which may rival that of Comet Arend-Roland in 1957.
Nicolaus Lefaudeux

Where to go and what to bring

For optimal viewing, drive far away from city lights and look up at a very dark sky.

If that’s not feasible, find a relatively dark spot outside of the city — perhaps on a hill or at the city’s edge — where you can face away from major light sources to see Comet A3. 

“Even if you live in an area with lots and lots of street lights, lots of smog, lots of smoke, lots of whatever, you still ought to go for it,” Kareta said.

Check the weather forecast before heading out. If the sky is expected to be cloudy all night, it may be worth planning for another evening. Bring warm layers and a chair or blanket to lay back on, as craning your neck for long periods can become uncomfortable.

If you have binoculars or a telescope, bring them along, as there’s no guarantee the comet will be visible to the naked eye. In some cities, local libraries offer binoculars or telescopes for borrowing.

How to look for the comet

Finding a comet in the sky is trickier than you might expect. You’ll need a few tips and techniques.

Once at your comet-watching spot, open your skywatching app to pinpoint exactly where the comet is, near a recognizable constellation like the Big Dipper.

Allow your eyes at least 30 minutes to adjust to the darkness. Avoid looking at your phone, as even a brief glance at a bright screen can reset your night vision.

If the comet doesn’t stand out immediately, scan the area. Your peripheral vision is more sensitive to faint objects, so you might spot the comet in the corner of your eye.

Look for a smudge, slightly larger than a star, but it won’t twinkle like stars do. It will appear more blurred with less defined edges and may seem elongated due to the comet’s tail of dust and gas streaming from its icy body.

Comet Tsuchinshan-ATLAS: The Comet of The Year is Here
As a bird photographer, Tobias Yoder of Campbellton, Texas, has dreamed of capturing a photo of a bright comet with a great horned owl. His wish came true on Oct. 1st. Details: 200mm lens, f/2.8, 4-second exposure.
Credit: Tobias Yoder

“If you look at it and it looks like it’s behaving differently than some of the stars nearby, that’s a really good sign that you’ve picked up on the right thing,” Kareta said.

Still uncertain? Try taking a long-exposure photo with your phone’s camera, which is available in most phone’s night settings. This will give you a clearer image of the comet than what your eyes can detect. If you can’t find Comet A3, Kareta suggests trying again a few days later.

“Go one night out, and then take a night off, and go back out. You’ll know better how to time it, how to get ready,” he said.

How to photograph the comet

If your phone camera isn’t capturing the comet, a DSLR camera might be more effective. Massey suggests taking a series of exposures.

You can also try taking a photo through your binoculars or telescope by holding your phone camera up to the lens. This method can be tricky, so it’s best to practice beforehand.

After this, Comet A3 won’t return for tens of thousands of years. “See it now or lose your chance,” Kareta said.


Comet Tsuchinshan-ATLAS: The Comet of The Year is Here

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