Comet Lemon - How Low Can You Go?

C/2025 A6 (Lemmon) is the technical name for a comet that made a sudden and brief appearance in our night sky this fall. Astrophotographers across the world all took their shot at this rare emerald beauty. Discovered only in the past year, Comet A6 was hyped to be one of the very few interstellar objects we would ever see in our lifetimes—meaning we thought it truly came from outside our solar system. That turned out not to be the case, but it still has a truly long, elliptical orbit of 1,150 years. In other words, we won’t see this beauty again until the year 3421. If you’re reading this blog in the distant future, take notes on how to capture this object the old 3rd-millennium way: blood, sweat, tears, and luck.

My first attempt at A6 came in early October. I knew it wouldn’t be visible to the naked eye, but I wanted to figure out exactly where, in practical terms, I’d have to set up for decent exposures. I woke up at 5:30 AM, knowing I needed to polar-align my scope while it was still dark. My very rough eyeball estimates told me Comet Lemmon would just clear the treeline around 6:30ish. With dawn quickly overtaking any chance of a shot, I had to work fast to get everything right. The first attempt wasn’t bad, but it left me craving more. I knew I had to wait a few weeks for Lemmon to reach its peak—October 20th.

As the days passed, more astronomers around the world started posting their images and talking about just how long Lemmon’s tail really was. They also described something fairly unusual for recent comets: the tail was extremely dynamic, changing almost imperceptibly between shots. That sounded so cool I couldn’t wait to see it for myself. But as October 20th approached, my excitement slowly turned to trepidation. Every morning, Comet Lemmon was getting lower and lower in the sky. I was running straight into the classic problem for astronomers in this part of the country—trees.

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I needed an alternative location. Since I don’t run off battery power, I needed a dedicated outlet and a fairly clear, unobstructed view of the northwestern sky. I decided to try my parents’ house. They have 5 acres in South Fayette. I’d need a long extension cord and perfect conditions. Fortunately (or unfortunately), we’d been in a drought, which meant clear skies. I gathered all my gear and told my mom I needed to do something crazy in the far corner of her property.

It turned out the trees there are very tall, most well over 75 feet. Still, my rough calculations using Google Maps to measure distance told me I should just make it, given the time of complete darkness, the angle, and the distance from the treeline. (That formula, for anyone wondering, is θ = arctan(h / d), where θ is the obstruction altitude in degrees.)

After polar-aligning around 6:45 PM, all I could do was wait for every last trace of the sun to disappear. I was also painfully watching my motorized mount dip slowly closer and closer to the treeline. In the end, I managed to grab about 10 images of beautiful Comet Lemmon. Do I wish I had more data? Of course! But as the old saying goes, “Sometimes the journey is more important than the destination.”