Using the 1911 refractor on the Observatory roof, astronomy students have measured the night sky over 60 kilometres of the valley.
Over two winters, a team of eighteen undergraduates took sky-brightness readings from 140 sites, some of them reached only on foot. The result is the first detailed map of light pollution across the valley, showing a corridor of genuinely dark sky that runs from the Observatory to the coast.
The county council has asked the students to present their findings at a planning hearing in November, where a proposal to protect the corridor from new street lighting will be discussed.
