How to Photograph Bright Comets: Capturing the Magic of Comet C/2023 A3 (Tsuchinshan–Atlas)

Comet A3, October 3rd 2024

Comets are among the most awe-inspiring objects in the night sky, offering rare opportunities to witness the beauty of the cosmos. In 2024, Comet C/2023 A3 (Tsuchinshan–Atlas) promises to be a dazzling visitor, potentially becoming bright enough for both naked eye and telescopic observation. Having seen and imaged many bright comets over the past few years, I can tell you firsthand that viewing a comet is not just a visual experience—it can be deeply emotional, something you'll carry with you forever.

My journey with comets began in 1996 when I first laid eyes on Comet Hale-Bopp. That single moment changed the course of my life, igniting a passion for astronomy and astrophotography. Fast forward to 2009, when Comet McNaught graced the skies—it remains, in my opinion, the greatest comet of all time. Every comet has a unique presence, and with Comet C/2023 A3 on the horizon, you have the chance to capture one of the universe’s most remarkable phenomena. Let’s dive into how to photograph this bright comet and immortalise its celestial beauty.

Comet McNaught 2009, Moonta, South Australia

1. Timing Is Everything

The first step in capturing a comet like C/2023 A3 is knowing when to look for it. Comets become visible as they approach the Sun, causing their icy surfaces to vaporise and form a glowing coma and tail. C/2023 A3 will likely be most visible as it approaches perihelion, expected around late 2024.

For the best chance of photographing it, keep an eye on updates about its position and brightness. Comets can be unpredictable in terms of visibility, but photographing one is worth the challenge. The early evening or pre-dawn hours, when the sky is darkest, will offer the clearest views.

2. Choosing the Right Equipment

Photographing a comet is a bit different from typical landscape photography due to the low-light conditions and the comet’s movement. Here’s the gear you’ll need:

• Camera: A DSLR or mirrorless camera with good low-light performance will allow you to capture the finer details of the comet’s structure.

• Lens: A wide-angle lens (14mm to 35mm) can capture the comet against a stunning night sky. If you want to zoom in on the comet’s nucleus or tail, a telephoto lens (70-200mm or longer) will reveal more detail.

• Tripod: To keep your camera stable during long exposures, a sturdy tripod is essential.

• Star Tracker (Optional): A star tracker can help you take longer exposures without trailing stars, allowing you to capture more light from the faint comet tail.
  
  
  
  

Skywatcher Star Adventurer Star Tracker

3. Camera Settings for Comet Photography

The correct settings will depend on the comet’s brightness, but these are good starting points:

• ISO: Set your ISO between 800 and 3200. You want enough sensitivity to capture faint details, but not so high that noise overtakes the image.

• Aperture: A wide aperture (f/2.8 – f/4) will allow you to collect more light, which is essential for low-light conditions.

• Shutter Speed: If you're not using a tracker, limit your exposures to between 5-30 seconds to avoid star trails. If you're using a star tracker, you can experiment with longer exposures.

• Focus: Achieving perfect focus is essential. Use live view on a bright star and manually adjust the focus until the star appears as a pinpoint.
  
  
  
  
  

4. Framing the Comet

Comets, particularly bright ones like C/2023 A3, can be quite large in the sky, with long tails that stretch across the stars. Consider your framing carefully: wide-angle shots will capture both the comet and some foreground, like landscapes or trees, while zooming in will allow you to capture intricate details of the comet’s nucleus and tails.

When I photographed Comet McNaught in 2009, the bright, fan-shaped tail filled the sky—it was an unforgettable sight. The tails of comets can be either a dust tail or an ion tail, and framing your shot to capture their full expanse can result in breathtaking images.

Comet Swan, Adelaide Hills, South Australia

5. Taking Multiple Exposures

To enhance the quality of your image, take multiple exposures and stack them using software like DeepSkyStacker ( PC ), Starry Night Landscape Stacking ( Apple ). Stacking helps reduce noise and increases detail in the comet’s tail. You can also take separate exposures of the foreground to blend later, ensuring you don’t overexpose any part of the landscape.

6. Post-Processing Tips

Once you’ve captured your comet, post-processing will help bring out its beauty:

• Contrast and Brightness: Adjusting contrast will make the comet’s nucleus stand out while also highlighting its fainter tails.

• Noise Reduction: Use noise reduction tools to smooth out any graininess caused by high ISO settings.

• Colour Enhancement: Comets often display vivid colours in their tails—adjust the hue and saturation to enhance the natural blues and golds.
  
  
  
  
  

7. An Unforgettable Experience

Viewing a comet, especially a bright one, can be an emotional and awe-inspiring event. I’ll never forget seeing Comet Hale-Bopp for the first time in 1996—its brilliance filled the sky, and it was as if the universe was whispering its secrets. Comet McNaught in 2009 moved me in the same way, and each comet I've photographed since has been a unique and powerful experience.

If you’ve never photographed a comet before, prepare yourself for an unforgettable adventure. With Comet C/2023 A3 (Tsuchinshan–Atlas) lighting up the sky, it’s your chance to create stunning images of one of nature’s most mysterious visitors.