Comet Tsuchinshan-ATLAS over Flattop Mountain

It is an extraordinarily rare shoot when I am able to make the best image I can envision. Almost always, I fall well short. But not this time.

As Comet C/2023 A3, better known as Comet Tsuchinshan-ATLAS, approached Earth after surviving its perilous passage around the sun, I began planning a shoot. The ultimate shot, as I envisioned it, would have several elements. The sky, of course, would have to be clear. The comet would have to be setting over some dramatic skyline. There would be a lake in the foreground to reflect the comet and the mountain backdrop. The wind would be calm, so the reflection would be sharp. Bright moonlight at just the right angle would create great detail in the land.

I used Starry Night to get data on the comet’s azimuth and altitude during the nights when it was expected to be at its brightest. I took that data to Photo Ephemeris Web to figure out where to go to see the comet setting over some dramatic skyline. To my delight, I discovered that on October 14, 2024, the comet would be setting over Flattop Mountain as seen from Sprague Lake in Rocky Mountain National Park. Not only would it be in the right direction; it would also be at the right altitude in degrees above the skyline. The nearly full moon would be rising to the southeast.

My wife Cora and I knew we would need an enormous amount of luck for all the elements to come together. On October 14th, in late afternoon, we drove to Sprague Lake, set up, and began waiting for sunset. Persistent clouds hung over Flattop Mountain and Hallett Peak. A steady breeze churned the surface of Sprague Lake. It seemed extremely unlikely that we would be able to make the ideal image I envisioned.

Sunset passed, and the sky began to grow dark. Clouds still blocked our view of the comet. The sole photographer who had set up nearby decided to leave. We were alone. As nautical dusk approached, the clouds began to dissipate and the wind grew calm. Slowly the comet emerged from the darkening sky. The nearly full moon, rising to the southeast, cast beautiful light on the dazzling scene before us.  We photographed until the comet set behind Flattop Mountain, immensely grateful for our good fortune. It will be 80,000 years before Comet Tsuchinshan-ATLAS returns to our skies.