In the middle of an ocean, where light pollution is entirely absent, you may experience the profound blackness that is Bortle 1 on the Bortle Dark-Sky Scale.
This scale was created by John E. Bortle in 1991 to help amateur astonomers compare the darkness of observing sites. It is a nine-level numeric scale that measures the brightness of the night sky and the stars within it at a particular location. It is, therefore, a way of quantifying the astronomical observability of things in the night sky and the interference caused by light pollution.
A rural sky would be at Bortle 3, a suburban sky at Bortle 5, a city sky at Bortle 8 and top of the scale, at Bortle 9, is the inner-city sky. In the inner-city you can see the Moon, and a few of the larger star clusters. That's it. And that's enough for me. I warm to the sodium glow that obliterates the stars. Bright lights, big city, cancel your subscription to Sky and Telescope magazine.
But back to the Bortles. Bortle 2 is as dark as it gets on dry land. There are only two Bortle 2 locations in the entire world (as ratified, it must be admitted, by the International Dark Sky Association). The first is in Natural Bridges, Utah and the second in Cherry Springs State Park, Pennyslvania.
But there is about to be a third.
And guess what. It's here. In Dumfries and Galloway. Glentrool in the Galloway Forest Park.
Be still my beating heart.
Lots to look forward to now!
Galloway Forest Park blogs here: http://gallowayforestpark.blogspot.com/
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