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C/2023 A3 (Tsuchinshan–ATLAS): Your Next Big Astrophotography Target?

Updated: Nov 2

Hey, fellow stargazers and space enthusiasts! Let's talk about something that's got the astronomy community buzzing—C/2023 A3 (Tsuchinshan–ATLAS), a newly discovered comet that has the potential to become one of the most exciting night sky spectacles in 2024. Whether you're just starting out with a telescope or you're a seasoned astrophotographer, this comet is likely to be on your watchlist soon. Here’s everything you need to know to get ready for this celestial visitor!


The Discovery: What’s the Deal with C/2023 A3?

C/2023 A3 (Tsuchinshan–ATLAS) is a long-period comet discovered in early 2023 by two different observatories: Tsuchinshan (also known as the Purple Mountain Observatory) in China and the ATLAS (Asteroid Terrestrial-impact Last Alert System) survey, which is based in Hawaii. The comet is currently far away but is expected to get brighter and more visible as it approaches the inner solar system in 2024.

Quick Stats:

  • Discovery Date: January 2023

  • Perihelion (closest approach to the Sun): October 2024

  • Expected Brightness: Possibly as bright as magnitude 0 (which could make it a naked-eye object!)

  • Tail Features: Predicted to have a significant gas and dust tail (hello, photogenic sky candy!)

The early projections suggest C/2023 A3 might be one of the brightest comets since C/2020 F3 (NEOWISE), which lit up our skies in 2020.


When and Where Can You See It?

If all goes according to plan—and comets are notoriously unpredictable—C/2023 A3 should put on its best show in October 2024. Around this time, the comet will be closest to the Sun, and we could get a view of its long, dramatic tail. While it will be visible across much of the globe, observers in the Southern Hemisphere, especially those of us down under in Australia, could get prime viewing opportunities as it climbs higher in the sky.

Mark these key dates on your calendar:

  • September 2024: The comet will become more visible in the evening sky.

  • October 2024: This is the peak period for viewing. The comet will be closest to the Sun on October 12, 2024, and to Earth on October 17, 2024.


How Bright Will It Get?

Comet brightness predictions can be tricky because their behaviour can change as they approach the Sun. Right now, early models suggest C/2023 A3 could reach a brightness around magnitude 0, which would make it visible to the naked eye, even from light-polluted areas. For those of us with telescopes and cameras, the comet should be a fantastic target for wide-field astrophotography.

It’s important to temper your expectations, though. Comets are fickle objects; they can flare up or fizzle out unexpectedly. But if all goes well, this could be one of the best cometary displays in years!


How to Photograph C/2023 A3

Now, let’s get into the juicy details for astrophotographers! Here’s a step-by-step guide to capturing this comet in all its glory.

1. Gear Up

While a naked-eye view will be cool, a good DSLR or mirrorless camera paired with a wide-angle lens will give you the full tail-and-nucleus experience. If you have a telescope, that’s even better! A tracking mount will be essential for longer exposures.

2. Location, Location, Location

Pick a dark sky site, like a remote beach or national park. Beachmere could be ideal—minimal light pollution and a horizon that’s often clear of obstructions. Get ready to stay up late or wake up early because comet hunting happens when the sky is darkest, usually a few hours before dawn.

3. Settings for Success

  • ISO: Start with 1600-3200. Adjust based on light pollution.

  • Aperture: Wide open! f/2.8 or wider.

  • Exposure time: 10–30 seconds to avoid star trails if you’re shooting with a standard tripod. If you’ve got a tracking mount, you can go much longer.

4. Focus on the Stars

Set your lens or telescope to manual focus and fine-tune on a bright star using live view or a Bahtinov mask. Comets move faster than most deep-sky objects, so be ready to adjust your framing during the session.

5. Processing Tips

Stacking multiple exposures in software like DeepSkyStacker will help bring out the details of the comet's tail and its faint features. Play around with contrast and curves to get the comet to pop against the starry background.


Why C/2023 A3 is Special

Comets have this magical way of connecting us to the outer reaches of the solar system. They’re ancient, icy visitors that carry cosmic dust and gas from the farthest parts of our cosmic neighbourhood. For us Earthlings, C/2023 A3 (Tsuchinshan–ATLAS) could be a once-in-a-decade opportunity to witness such a spectacle, especially if you missed out on NEOWISE or other recent bright comets.

And even if it doesn’t live up to its full potential, following this comet’s journey through space is a reminder of the unpredictable beauty of the cosmos. As it gets closer to perihelion, we’ll learn more about its structure and behaviour, so stay tuned for updates!


What If It’s a Dud?

We’ve all been there—a comet that was supposed to be “the brightest in decades” fizzles into a faint, fuzzy blob. But that’s part of the fun, right? The sky is full of surprises, and comets are particularly notorious for doing their own thing. Even if C/2023 A3 doesn’t turn out to be the showstopper we hope for, it’s still an opportunity to enjoy the night sky, practice your photography, and be part of the worldwide community of observers tracking its journey.


Final Thoughts

C/2023 A3 (Tsuchinshan–ATLAS) is shaping up to be a major celestial event for 2024, and whether you’re observing with just your eyes or through a camera lens, it’s worth keeping an eye on. With potential naked-eye visibility and a tail that could stretch across the sky, this comet has the chance to be a real highlight.

Start planning your observation sessions now, and dust off your astrophotography gear—you won’t want to miss this one. Plus, comets like this don’t come around often, so let’s enjoy it while we can!


Clear skies and happy comet hunting!


The Majestic Tail of Comet C/2023 A3 Reflecting Over Beachmere


On the evening of September 30, I captured a breathtaking image of Comet C/2023 A3 (Tsuchinshan–ATLAS) from the serene shores of Beachmere, QLD. The comet's tail stretched across the sky, spanning over 20 degrees — about the length of six full moons lined up in a row! The tail glowed in vivid detail, an ethereal stream of dust and gas, illuminated by sunlight.

What made the moment even more magical was the calm water below. As I set up my camera, I noticed the comet's tail reflecting softly on the ocean surface, creating a perfect mirror of celestial beauty. The shimmering tail seemed to flow seamlessly from the sky to the sea, drawing a line between two worlds — the vastness of space above and the stillness of Earth below.

This alignment between space and sea created a composition that highlighted the comet’s incredible presence. It was a sight that made the stillness of the night feel even more profound. Capturing such an awe-inspiring display of nature’s grandeur was truly a once-in-a-lifetime experience.



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