2025-06-30

I ordered a Unihedron SQM-L (sky quality meter) and it came the other day. Even though tonight was a 30% moon and its brightness would affect the outcome of the sky quality test, I decided to give it a shot after my observation of Lacus Mortis. I’m expecting my backyard to fall around a 20 mpsas (magnitudes per square arcsecond), and the meter hit 19.75 mpsas. I also did not wait until true-dark which is around 11:15PM.

With the news that flood lights are being installed at Terry Peak for night-time skiing, hopefully this meter can help me find a new dark sky site!

9:46PM

Image

Very crisp and clear observation. A little bit of turbulence came while I was sketching, but overall the conditions tonight were excellent.

Lacus Mortis is an interesting feature. With the way the shadows were being cast tonight it almost appeared to be a sinus (bay) more than a lake.

North in the sketch is to the right. The Bürg crater is directly in the center of the lake. The Hercules crater can be seen on the north-east edge of the sketch. Hercules was already observed back in [[2024-05-12]].