C/2023 A3 (Tsuchinshan-ATLAS): Will It Be The Next Great Comet? (2024)

Comet C/2023 A3 (Tsuchinshan-ATLAS) promises to be a highlight of autumn 2024. Discovered in early 2023, it’s been called a potential “comet of the century”. The comet is already visible in both hemispheres — you can spot C/2023 A3 using the free astronomy app Sky Tonight. Let’s see if the comet lives up to the hype and when it will be visible to the naked eye.


  • What makes C/2023 A3 (Tsuchinshan-ATLAS) special?
  • How to find C/2023 A3 (Tsuchinshan-ATLAS) in the sky?
  • Is the comet C/2023 A3 (Tsuchinshan-ATLAS) visible now?
    • Sudden burst of brightness in April 2024
    • C/2023 A3 (Tsuchinshan-ATLAS) visibility forecast for 2024
    • C/2023 A3 (Tsuchinshan-ATLAS) approaching the Earth in 2024: path through the Solar System
  • Discovery of C/2023 A3 (Tsuchinshan-ATLAS)
    • Meaning of the comet C/2023 A3 (Tsuchinshan-ATLAS) name
  • Best time to observe C/2023 A3 (Tsuchinshan-ATLAS): how bright will it get? 🤩
  • C/2023 A3 (Tsuchinshan-ATLAS) nucleus: the size matters
  • Will C/2023 A3 (Tsuchinshan-ATLAS) become the next great comet?
  • Comet Tsuchinshan-ATLAS: Bottom line

“Comets are like cats: they have tails, and they do precisely what they want.”

― David H. Levy, Comets: Creators and Destroyers.

What makes C/2023 A3 (Tsuchinshan-ATLAS) special?

The quote above, which belongs to David H. Levy, a Canadian astronomer and discoverer of many comets, is perfect for C/2023 A3 (Tsuchinshan-ATLAS). First of all, C/2023 A3 (Tsuchinshan-ATLAS) is expected to grow a beautiful cometary tail; fainter comets usually don’t have prominent tails at all. After passing by the Sun at a distance similar to Mercury's orbit, C/2023 A3's coma of dust and ice will heat up considerably. As the ice particles evaporate, they will quickly escape into space, taking with them a large amount of dust that will extend into a long, bright tail. As history shows, comets that pass close to the Sun have the most impressive tails, formed soon after being "roasted" by the Sun's heat. And this is the case with comet C/2023 A3!

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Also, the brightness of C/2023 A3 (Tsuchinshan-ATLAS) is unpredictable and depends heavily on its activity in the coming months. However, most sources agree on one thing: C/2023 A3 (Tsuchinshan-ATLAS) is likely to be visible to the naked eye. If we're lucky, it could become exceptionally bright and even outshine C/2020 F3 (NEOWISE) from summer 2020. It's been a long time since we've seen such a bright comet, so observers are very excited about C/2023 A3.

Remember that comets become visible to the naked eye at around magnitude 3. The magnitude scale measures the total light spread over the object, so the naked-eye visibility limit is lower (mag 6.5) for pinpoint sources of light, like stars or planets, and higher for diffuse objects, like comets or galaxies.

In addition, C/2023 A3 (Tsuchinshan-ATLAS) will favor the Northern Hemisphere being perfectly visible there. The last time an exceptionally bright comet was visible from the northern latitudes was in 1997 when Comet Hale-Bopp lit up the sky.

How to find C/2023 A3 (Tsuchinshan-ATLAS) in the sky?

You can spot C/2023 A3 (Tsuchinshan-ATLAS) with the Sky Tonight app. Open the app, and tap the magnifier icon at the bottom of the screen. Then type “C/2023 A3” and tap the target icon next to the corresponding search result. The app will show you the comet’s current position in the sky for your location. Point your device at the sky and follow the white arrow to find it.

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Is the comet C/2023 A3 (Tsuchinshan-ATLAS) visible now?

Currently, C/2023 A3 (Tsuchinshan-ATLAS) is still faint, with a magnitude of about 10. It is visible in the late evening in the northern and southern latitudes. The comet is slowly drifting through the zodiacal constellation Virgo, passing north of the constellation's brightest star, Spica (mag 1.0), and just beneath Heze (mag 3.4) (the directions are reversed in the Southern Hemisphere).

Observers with small telescopes can view C/2023 A3 in the sky. It can also be captured with a DSLR camera. In photos, the comet looks like a fuzzy, slightly elongated object. Larger telescopes and more sophisticated cameras will reveal the comet’s tail.

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Sudden burst of brightness in April 2024

In early April 2024, comet C/2023 A3 (Tsuchinshan-ATLAS) unexpectedly brightened from magnitude 11 to magnitude 10. Astronomers believe this sudden brightening was due to the comet's approach to opposition on April 18. During opposition, we face the comet with the Sun behind us, making the dust in the coma appear as bright as possible. Now that the comet has passed opposition, its brightness increase will slow down.

But this change doesn't affect the comet's future visibility. The big question remains — what will happen when this icy visitor passes close to the Sun in September? Keeping a close eye on the comet now will help gather crucial information. We'll share our thoughts on the comet's brightness further in this article. Also follow our Instagram account, where we quickly post all the latest news.

C/2023 A3 (Tsuchinshan-ATLAS) visibility forecast for 2024

Here are some predictions for 2024 monthly visibility:

  • May: 10-11 magnitude, visible in the evening;
  • June: 9-10 magnitude, favors the Southern Hemisphere. Bad observing conditions in the Northern Hemisphere due to bright summer nights and lower declination from the Sun;
  • July: 8-9 magnitude, still favoring Southern Hemisphere, evening visibility;
  • August: 4 magnitude by the end of the month, but too close to the Sun;
  • September: 3-4 magnitude, moves away from the Sun and begins to appear in the morning sky in the Southern Hemisphere. Short observation window, a good opportunity for capturing the comet’s tail. From September 27 to October 2, it appears in the morning in the Northern Hemisphere.
  • October: the best month for observations in the Northern Hemisphere. Around its closest approach to Earth on October 12, the comet will be at its brightest (magnitude about 0-1). It will be located relatively high above the horizon in the evening sky.
  • November: 4.5-8 magnitude, visible in the evening. Rises higher in the Northern Hemisphere after sunset.
  • December: 8-10 magnitude. Gradually moves closer to the Sun in our sky, rising lower above the horizon. Not visible from the Southern Hemisphere.
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Please note that comets are very unpredictable space objects, and data (especially apparent magnitude) can change quickly. However, we’ll do our best to keep you up to date.

C/2023 A3 (Tsuchinshan-ATLAS) approaching the Earth in 2024: path through the Solar System

Here, you can get a month-by-month guide on the comet’s journey through the Solar System in 2024. We also made a video to visualize the comet's trajectory in space. Watch it to see how the comet's brightness and location will change over time.

  • February-July: for six months, C/2023 A3 is traveling between the orbits of Jupiter and Mars. By the end of this period, the comet will be 2.04 AU away from the Earth.

  • August: comet C/2023 A3 will reach the area between the Earth and Mars. By the end of the month, the comet will approach the Earth as close as 1.76 AU.

  • September: comet C/2023 A3 will enter Venus’s orbit. On September 27, the comet will pass perihelion, meaning it will come the closest to the Sun, at a distance of 0.39 AU. During this period, the comet may break apart under the impact of the high temperature.

  • October: if C/2023 A3 survives perihelion, then on October 12, it will come the closest to the Earth and will be at a distance of 0.48 AU from our planet. It will reach maximum brightness and be observable even with the naked eye.

  • November: C/2023 A3 will gradually lose its brightness as it will move away from the Earth. By the end of the month, the distance between the comet and our planet will increase to 1.94 AU. For the next 20 years the comet will be moving toward the edge of the Solar System and will not return for another 26,000 years.

Discovery of C/2023 A3 (Tsuchinshan-ATLAS)

On February 22, 2023, the ATLAS telescope in South Africa detected a new faint object that was proven to be a comet. It was temporarily designated as A10SVYR. The comet was also independently captured by a telescope at Purple Mountain Observatory (Zijinshan Astronomical Observatory) on January 9, 2023. It was added to the list of objects awaiting confirmation, but after no follow-up observations were reported, it was removed on January 30, 2023, and was considered lost. Based on the comet naming system, the comet received the names of both observatories and was officially named C/2023 A3 (Tsuchinshan-ATLAS).

Shortly after its discovery, observations up to April 2022 were found in the archives of the Minor Planet Center. C/2023 A3 (Tsuchinshan-ATLAS) is a long-period comet that completes one orbit around the Sun in 80,660 years.

Meaning of the comet C/2023 A3 (Tsuchinshan-ATLAS) name

The name of the comet contains data about where and when the comet was first seen:

  • The letter C indicates a non-periodic comet – comets of this type originate from the Oort cloud and may pass through the Solar System only once or take from 200 to thousands of years to orbit the Sun;
  • 2023 A3 means the comet was discovered in 2023, in the first half of January (this corresponds to the letter A in the IAU comet naming system), and was the third such object discovered in the same period;
  • Tsuchinshan-ATLAS means the discovery was made using telescopes of the Purple Mountain Observatory (Zijinshan Astronomical Observatory) and Asteroid Terrestrial-impact Last Alert System (ATLAS).

Best time to observe C/2023 A3 (Tsuchinshan-ATLAS): how bright will it get? 🤩

C/2023 A3 (Tsuchinshan-ATLAS) favors the Northern Hemisphere, where it will be visible to the naked eye in October 2024. It’s hard to predict the exact brightness of the comet — most tend to think it will be about 0-1 magnitude.

On October 12, 2024, C/2023 A3 (Tsuchinshan-ATLAS) will pass close to the Earth (0.48 AU) and should reach its peak brightness around that time. According to astrovanbuitenen.nl, C/2023 A3 might brighten up to -4.0 magnitude (due to the effect of forward scattering).

The SETI institute forecasts that the comet’s peak brightness can range from a magnitude of 0.6 to -6.6. By comparison, the comet Hale-Bopp, one of the most widely observed comets of the 20th century, had a peak magnitude of -1.8. The so-called green comet C/2022 E3 (ZTF), which was trending at the beginning of 2023, reached a maximum magnitude of 5.4. The famous NEOWISE (C/2020 F3) peaked at 0.9.

To extend the show, start looking for the comet in the morning sky at the end of September. It will be visible very low in the sky before sunrise. On September 27, C/2023 A3 (Tsuchinshan-ATLAS) will make its closest approach to the Sun (0.39 AU). According to astrovanbuitenen.nl, at this time, C/2023 A3 might reach a magnitude of 0.5, being easily visible to the naked eye.

After the perihelion, C/2023 A3 (Tsuchinshan-ATLAS) will disappear for a while and reappear in the evening sky in early October 2024. It will remain an evening object until the end of the month. However, after October 12, the comet will fade out rapidly and won’t be visible to the naked eye by the end of the month.

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C/2023 A3 (Tsuchinshan-ATLAS) nucleus: the size matters

A comet’s brightness is largely determined by the size of its nucleus. For instance, the Hale-Bopp comet's nucleus is about 60 km (37 mi) in diameter, and Halley's comet has a 15 km (9 mi) nucleus, which is considerable for a short-period comet. Typically, a cometary nucleus is only a few kilometers in diameter.

So, what about the size of C/2023 A3's nucleus? Unfortunately, we can't say for sure. Even with modern, advanced equipment, the nuclei of long-period comets are usually difficult to see, because they’re obscured by dense clouds of dust from cometary activity. This means we rely on indirect methods for approximate estimates.

Some estimates suggest its nucleus is between 6 and 15 km (4 to 9 mi) in diameter. This gives hope that the nucleus won't disintegrate as it approaches the Sun, unlike C/2012 S1 (ISON), whose 1 km nucleus fell apart during perihelion in 2011. Other astronomers suggest the nucleus could be between 20 and 40 km. If this is true, we could be in for a spectacular celestial show in autumn 2024!

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Will C/2023 A3 (Tsuchinshan-ATLAS) become the next great comet?

C/2023 A3 (Tsuchinshan-ATLAS) may well be the next great comet. Although there is no official definition of the term, great comets are usually exceptionally bright. So bright, in fact, that even a casual observer who isn't intentionally looking for a comet will notice it. Such comets also become well-known outside the astronomical community. The comets Hale-Bopp in 1997 and McNaught in 2007 were among the last comets to be called great. Again, comets are very unpredictable bodies, and there is always room for a surprise. For now, all we have to do is wait patiently for C/2023 A3's performance in autumn 2024.

Comet Tsuchinshan-ATLAS: Bottom line

The comet C/2023 A3 (Tsuchinshan-ATLAS) has great potential and may become visible to the naked eye by October 2024. According to some forecasts, it could reach 0-1 magnitude or brighter. For now, it is only visible through a telescope. Use the Sky Tonight app to locate C/2023 A3 (Tsuchinshan-ATLAS) in the sky. The app's Time Machine feature will allow you to see the comet's position in your sky in the future. Watch our video tutorial and learn how to use this feature.

C/2023 A3 (Tsuchinshan-ATLAS): Will It Be The Next Great Comet? (2024)
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