The Guide

De­mys­ti­fy­ing dark sky des­ig­na­tions.

Sky at Night Magazine - - CONTENTS -

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.dark­, 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.

Defin­ing 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

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