albertw wrote: The local towns and villages don't have an impact as much as I had suspected. 21.2+ readings were obtained near Tinahealy, Baltinglas, Donard. Though the SQM is looking at the zenith, due to low angle scatter proximity to streetlights will affect the horizon brightness.
The only way to really quantify that is with an all sky image. Unfortunately I don't have a full frame DSLR with a wide fish eye lens (e.g.
www.sigmaphoto.com/shop/8mm-f35-ex-dg-circular-fisheye-sigma
). On the off chance that anyone else does the standard settings are:
ISO: 1000
Aperture: fully open (f/3.5)
Shutter Speed: 180s (in places with more light pollution you will need a shorter exposure time, around 120s)
Focus: Manual, infinity
Camera should be mounted on a tripod and pointed at the zenith.
If you have the ability to take such images, from anywhere around the country not just Wicklow, then we'd appreciate getting the images for analysis.
Cheers,
~Al
  