Clouds, Moon, and a Lesson

On December 6th I visited Geumsan-gun, the southern tip of Chungcheong province. Staying at my grandmother’s place, I planned an ambitious stargazing session, expecting crystal clear weather from the forecast.

The forecast gave us a suspicious clear window between 7 p.m. and 0 a.m., so I carefully planned Messier objects and double stars for the best route. The plan was: M31 (Andromeda Galaxy), M15 (Perseus Cluster), M39 (Pyramid Cluster), M34 (Spiral Cluster), M33 (Pinwheel Galaxy), the Castor double star, M42 (Orion Nebula), and M45 (Pleiades).

My suspicions were confirmed when the sky remained extremely cloudy throughout the night. Not a patch of viewing window. But this was something out of my hands, and something every star nerds live with. What taught me a lesson, though, was a 30-minute clear sky between 3 a.m. and 4 a.m.

As I checked outside at one-hour intervals, I noticed a partially clear sky near 3:30. After quickly setting up my scope, an important lesson hit; the full moon was almost in transit. I could see my clear shadow off the moonlight, and the entire sky was lit up as if it was urban nightfall.

The only viable option, especially after a 6-hour discrepancy, was the Pleiades cluster (M45). When I saw even the brightest cluster was covered in static clouds, I also noticed that Betelgeuse and Rigel was barely, just barely visible.

The full moon in transit was a game changer. It renders deep sky viewing impractical, even at darker sites. This lesson could not have been taught better today.

As I hesitantly decided to switch to Jupiter, the bright planet was covered with clouds. As I turned to the moon surface to wait for clearance, the surface flickered within the eyepiece and died out, as if someone turned off the fuse. Looking up, the entire sky was back in the complete shadow of clouds, gleaming a yellowish gray with moonlight.