C/2023 A3 (Tsuchinshan-ATLAS): How and Where to See It Tonight?
The brightest comet in over a decade is still visible in the night sky! C/2023 A3 (Tsuchinshan-ATLAS) is fading away, leaving the inner Solar System, but if you grab a pair of binoculars, you can still catch it in the evening over the western horizon. Not sure where to look? No problem! Just download the Star Walk 2 app, and it'll guide you directly to the comet. Curious for more cool facts and viewing tips? Read on to learn all the details.
Contents
- What makes C/2023 A3 (Tsuchinshan-ATLAS) special?
- Tsuchinshan-ATLAS Tracker: how to find C/2023 A3 in the sky
- Where to see the comet C/2023 A3 (Tsuchinshan-ATLAS) now?
- How to photograph Comet C/2023 A3 (Tsuchinshan-ATLAS)?
- Is C/2023 A3 (Tsuchinshan-ATLAS) a great comet?
- Discovery of C/2023 A3 (Tsuchinshan-ATLAS)
- 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?
First of all, C/2023 A3 (Tsuchinshan-ATLAS) is the brightest comet in the last 13 years and visible to the naked eye! On October 2, it reached a magnitude of 0.4, overtaking the famous C/2020 F3 (NEOWISE) (peak magnitude 0.9) from summer 2020. From around October 11 to October 20, Comet Tsuchinshan-ATLAS was visible to the naked eye from the Northern Hemisphere — thousands of observers have reported their naked-eye observations.
Also, C/2023 A3 (Tsuchinshan-ATLAS) has grown a beautiful long cometary tail. It's already 21° long — about 42 times the size of the Full Moon's disk. After passing the Sun at a distance similar to Mercury's orbit, C/2023 A3's coma of dust and ice has heated up considerably. As the ice particles evaporate, they quickly escape into space, taking with them a large amount of dust that will extend into a long, bright tail. History shows that comets that pass close to the Sun have the most impressive tails, formed soon after being "roasted" by the Sun's heat. This is the case with comet C/2023 A3!
In addition, in the middle of October, C/2023 A3 (Tsuchinshan-ATLAS) favored 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.
Bonus: Comet Tsuchinshan-ATLAS has temporarily turned into a unicorn! For a while, it showed a thin streak of light opposite its dust tail, resembling a unicorn’s horn. In astronomy, this phenomenon is known as an anti-tail. It forms from the largest and heaviest dust particles, which the solar wind struggles to push away, so they appear behind the comet as seen from Earth. The anti-tail becomes visible only when Earth is crossing the comet’s orbital plane, which occurred from October 13 to 15.
Tsuchinshan-ATLAS Tracker: how to find C/2023 A3 in the sky
You can spot C/2023 A3 (Tsuchinshan-ATLAS) with Star Walk 2. Open the app and tap the magnifier icon at the bottom left of the screen. Then type “C/2023 A3” and tap 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 the comet.
Where to see the comet C/2023 A3 (Tsuchinshan-ATLAS) now?
Comet C/2023 A3 (Tsuchinshan-ATLAS) is now visible above the western horizon about an hour after sunset (the exact time depends on your latitude). The comet is fading fast, but you still have a chance to catch it.
To see the comet, grab a pair of 10x50 binoculars or something with a higher magnification and enjoy this space guest! Another way to see it is to photograph C/2023 A3 with a camera because a long exposure of a few seconds will show it more easily. You can also try a smartphone with an advanced night mode.
C/2023 A3 (Tsuchinshan-ATLAS) visibility forecast for 2024
Here are the predictions for the visibility of C/2023 A3 (Tsuchinshan-ATLAS) in the coming weeks. The lower the magnitude, the brighter the comet appears! The brightest objects have negative magnitude values.
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November: from 5 to 9 mag, visible in the evening, about an hour after sunset. Rises higher in the Northern Hemisphere, but is visible from both hemispheres. Travels from the constellation Ophiuchus to the smaller Serpens Cauda. Use binoculars or a small telescope to view the comet.
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December: from 9 to 11 mag, gradually moves closer to the Sun in our sky, rising lower above the horizon. Not visible from the Southern Hemisphere.
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January 2025: from 11 to 12 mag, very faint, available to observers from the Northern Hemisphere with a 8-inch telescope. Not visible from the Southern Hemisphere.
To track the exact position of Comet Tsuchinshan-ATLAS from your location, use the Star Walk 2 astronomy app. The app provides a personalized sky map for your site. You can also use the Time Machine feature (located in the upper right corner) to visualize the comet’s position at different times. Don’t miss out on capturing this rare celestial event!
Remember that comets become visible to the naked eye at around magnitude 4. 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.
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.
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October: on October 12, C/2023 A3 passed the closest point to the Earth and was at a distance of 0.47 AU (71 million km or 44 million miles) from our planet. This is when the comet reached its maximum brightness and became visible to the naked eye.
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November: C/2023 A3 gradually loses brightness as it moves away from Earth. By the end of the month, the distance between the comet and our planet will increase to 1.94 AU, about three times farther away than Mars.
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December: C/2023 A3 leaves the inner Solar System. Over the next 20 years, the comet will be moving toward the edge of the Solar System. Comet Tsuchinshan-ATLAS will not return for another 80,660 years, or perhaps not at all. According to NASA, the comet's path may take it out of the Solar System altogether.
How to photograph Comet C/2023 A3 (Tsuchinshan-ATLAS)?
Whenever the sky is dark enough, try to take photos of Comet C/2023 A3 (Tsuchinshan-ATLAS). To photograph the comet, you'll need:
- DSLR or mirrorless camera;
- Sturdy tripod;
- Wide-angle or zoom lens.
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Camera setup: Use manual mode to control settings. Set ISO between 1600 and 3200 depending on the comet's brightness. Use a wide aperture (f/2.8–f/4) for more light.
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Focus: Manually focus on a bright star or the Moon.
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Exposure: Set exposure time between 10 to 30 seconds to avoid star trailing.
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Location: Choose a dark site with minimal light pollution. Use apps like Star Walk 2 or Sky Tonight to track the comet’s location.
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Image stacking: For better detail, take multiple shots and stack them using programs like DeepSkyStacker or RegiStax. Stacking can enhance the comet’s tail and reduce noise.
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Post-processing: Use editing software like Photoshop to adjust brightness, contrast, and sharpness for a polished final image.
Bonus tip: Do some research on what settings and equipment other astrophotographers are using to capture comet shots. The Comet Watch Facebook group is a great resource where you can ask questions, learn from experienced photographers, and find plenty of useful information.
Is C/2023 A3 (Tsuchinshan-ATLAS) a great comet?
While there's no strict definition for a "great comet", they’re 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.
So, did C/2023 A3 (Tsuchinshan-ATLAS) achieve such fame? It certainly has made headlines around the world. As for its brightness, while it’s the brightest comet we've seen in the past decade, it didn’t quite reach the dazzling brilliance of Comet Hale-Bopp in 1997. Ultimately, the astronomical community will decide if Comet Tsuchinshan-ATLAS earns the title of a "great comet."
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).
Comet Tsuchinshan-ATLAS: Bottom line
Comet C/2023 A3 (Tsuchinshan-ATLAS) put on a fantastic show in mid-October, becoming visible to the naked eye — and it's not over yet! Although the comet is fading, there's still time to spot it with a pair of binoculars or capture some beautiful photos. Use the Star Walk 2 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 to learn how to use this feature.
