Sark: Night 1
Just walked east to west across Sark taking SQM measurements, from La Valette to La Fregondee, around 2km worth of data in more or less a straight line. Readings every 100m or so means that there isn’t much variation, with the darkest reading being 21.53 magnitudes per square arcsecond just west of the mill on the highest point of the island, and the brightest reading being 21.27 magnitudes per square arcsecond outside the brightly lit Mermaid Pub. To all intents and purposes though the readings were the same across the island, and it confirms what we suspected; that Sark is dark, but not as dark is it would be were it not next to Guernsey and Jersey, both of which contributed visibly towards skyglow. The best observing site so far is next to the old mill, the highest point on Sark, and indeed in all the Channel Islands. This tall tower would make an ideal observatory, but that might go against local conservation issues…
Dark skies of Sark:
Canon 5D with Sigma 8mm 180° EX DG fisheye lens f3.5, 120 seconds, ISO1000
In the above image you can see the glow from Guernsey (WNW, top right), Jersey (SSE, bottom left), and France (NE, top right). Despite the glow you can see many hundreds, indeed thousands of stars. Remember, this image was deliberately exposed to reveal light pollution, and so the sky looks more light polluted than in reality it is. This is in order to identify the worst culprits for light pollution. You can still make out the familiar shapes of the Plough, Orion the Hunter, Mars, Saturn and the Milky Way (just). For a high-res version visit my Flickr page
Now, to bed.