Comet Lemmon: October Highlight

And how I ended up capturing it above a glacier in Switzerland

Author

Angel Fux
November 08, 2025

Every now and then, a comet passes close enough to be visible from Earth. And this fall, we had a rare chance to see one of them with our own eyes: Comet C/2025 A6 (Lemmon).

This comet was only just discovered earlier this year, in January 2025, by the Mount Lemmon Survey in Arizona, which is why it carries the “Lemmon” name. It’s a non-periodic comet, meaning it doesn’t orbit the Sun on a regular schedule like Halley’s Comet does. Based on current estimates, its orbit takes well over a thousand years, so we won’t be seeing this one again in our lifetimes.

Even though it wasn’t the brightest comet ever, it was still striking for those of us keeping an eye on the sky. One of the first things people noticed was its green glow near the nucleus, something that often happens with comets due to the presence of diatomic carbon C₂.

Had to do my research there so here it is:

When this molecule gets hit by sunlight, it fluoresces and produces that familiar green tint. This glow doesn’t last long near Earth, the molecules break down quickly in our atmosphere, but out in space and under the right conditions, it becomes visible through telescopes or long-lens photography.

Another really interesting part of this comet was its tail. Depending on when and where it was observed, people saw a wide, changing structure, sometimes straight, sometimes wavy, and occasionally shaped by solar wind. Most comets actually have two tails: a dust tail (from small solid particles released by the comet as it warms up) and an ion tail (charged gas particles that respond to the Sun’s magnetic field). The result is a dynamic, evolving shape that changes from night to night, which is exactly what made Lemmon so interesting to shoot.

Image by Angel Fux

How I photographed it

This was only my second attempt at photographing a comet, but the first time I actually planned for it in a more technical way: with a star tracker, a longer focal length, and a layered approach to build the image piece by piece.

I went to one of my favorite views above the Aletsch Glacier. It’s dark enough, quiet, and gives a great view of the sky without much light pollution. And it is facing northward, exactly where the comet would be visible.

I planned the shoot for after the sunet, when the comet was better aligned with the landscape. It was sitting just beneath the Big Dipper, which made it easy to locate.

The final image was built from three different layers:

  1. The comet itself

    I shot the comet with a 200mm lens (EXIF: 185mm, 90sec, f/3.2, ISO 1600) on a star tracker, to pick up as much detail in the tail as possible. Since comets move differently than the background stars, I couldn’t just use normal stacking tools, they would blur or misalign the nucleus. So I had to manually align and stack the comet frames in Photoshop to bring out the delicate tail structures.

  2. The night sky

    Then, I switched to a wider lens (EXIF: 22mm, 90sec, f/3.2, ISO 1250) to capture the sky around the Big Dipper and give the scene some context. I didn’t use the full width in the final image, but it gave me a good base to blend with the comet close-up. My goal was to focal blend the comet with the sky so that both could be seen clearly.

  3. The foreground

    I shot the landscape during nautical twilight, when there’s still just enough light to pick up the glacier’s textures. I also included myself in the frame, standing in the foreground, mostly for scale, and to quietly anchor the image in a human perspective.

The post-processing side

This was a fairly complex edit, especially the comet part. Because of its movement and brightness, there wasn’t really an “automated” way to stack it.

I had to do it manually, frame by frame, and then match it back to the wide sky shot and the landscape. It took quite a bit of time, but that’s also what I love about these kinds of projects, they’re not quick, but very rewarding.

The words that come with the final image

If you’ve been following my work for a while, you probably know that I love combining photography with writing. Not just to show what I saw, but to try and share what it felt like to be there.

So below is the text inspired by the image:

MIRROR

“Dear friend,

I’m writing to you while I can, while I’m here. I’m only passing, my time is brief, and I know yours is too. But since our orbits cross for a moment, let me leave you these words.

Some encounters will shift your path entirely. Don’t be afraid when they do. You’ll change along the way, and that too is part of it. You were never meant to remain the same. Stillness was never your nature.

There will be moments when you feel alone, when no one quite understands you. Loneliness will try to convince you to fade into others’ light. But remember, just because you shine in a different colour doesn’t mean you should dim it to match others’.

In a way, I see myself in you. We both burn for a moment, then move on, leaving a faint trail behind. It isn’t a tragedy. It’s simply the way of things.

Keep moving. Forward, always.

Yours for a brief moment in time,

Lem(m)on”

Angel

In case you missed it…

Comet Lemmon wasn’t a major mainstream event, but for those of us out at night, it was a quiet reminder of how much is still unfolding above us. These chances don’t come often and when they do, they don’t stick around long.

Below I’ll be sharing a few examples of how others around the world captured it too different techniques, different skies, and a lot of variety in how this same comet was seen.

And if you also went out to shoot it, or even just tried, feel free to share your version. I’d love to see what you came up with. Everyone sees the sky a bit differently, and that’s part of what makes these moments special to share.

Until the next one,

Angel