Demystifying dark sky designations.
Night-time light pollution affects nearly 80 per cent of the world. That was the headline finding from a study published in mid 2016 by the Light Pollution Science and Technology Institute in Italy. The study also announced that a third of people on Earth can no longer see the glimmering band of the Milky Way. Clearly, amateur astronomers have a lot to compete with in order to get a decent view of the night sky.
Much work is already being done by concerned bodies to preserve darkness or else achieve it where light pollution looms, resulting in an explosion of sites with ‘certified’ skies – places where you can be sure of a certain level of darkness or sky quality. You may have come across the terms for some of them, such as ‘Milky Way class’ sites and ‘Dark Sky Reserves’, within this very magazine.
Many of these designations come from the International Dark Sky Association (IDA; www.darksky.org), founded in 1988 to support and reward those seeking to improve the quality of the night skies above their homes, towns, cities and even national parks. It works with councils, communities and legislators globally to reduce the glare of artificial lighting, and much of its work involves the introduction of lighting that is more sympathetic to maintaining natural darkness.
The IDA’s Dark Sky Places programme designates the darkest regions around the world in five categories: International Dark Sky Communities, Parks, Reserves, Sanctuaries and Dark Sky Developments of Distinction. These are terms you may With Iain Todd have come across, but may still be unsure exactly what they mean.
Towns, cities, municipalities and other populated areas may apply to be recognised as an International Dark
Sky Community, provided there exists evidence of “exceptional dedication” to the dark-sky cause. Typically, such communities are legally incorporated entities, meaning they are free to enforce their own outdoor lighting policy. This includes islands like Coll in Scotland and Sark in the Channel Islands.
Even in rural areas light pollution from nearby cities can cause huge problems for astronomers