[troypiggo (Troy)]

Originally Posted by alexch

Thanks,

That natural skyglow is sometimes called a "permanent, low-grade aurora". It is a natural phenomenon and is is caused by various processes in the upper atmosphere, more here:
http://astrobob.areavoices.com/2009/...true-darkness/
and here:
http://en.wikipedia.org/wiki/Airglow

Cheers,
Alex

Thanks for that