Evening 16 July - SQM readings
Our library has a Starry Sky kit supplied through the Montana Learning Center. It contains a Unihedron Sky Quality Monitor (SQM) , a small Planisphere, a small red flashlight, and some documentation Didn't set up a telescope tonight, but took the SQM from the libraries Starry Sky kit out to measure the skies brightness. The observatory walls are up, so I took readings from in there. The walls are 5' tall, so for the first readings I held the SQM just low enough in the by the pier to be sure no outside light. Three consecutive readings at zenith were 21.36, 21.37, and 21.35, for an average of 21.35 mpas. I then did three readings pointed at zenith from the top of the telescope, which is about 6” higher than the wall. These readings were 21.33, 21.27. and 21.28 for an average of 21.29 mpas. I pointed it about 20 ยบ above the north horizon and it read 21.14 mpas. Pointed about the same above the south horizon it was 20.06 mpas. Our small town is 1 mile south of us, and there is...