Richard- I still keep in touch with one of Tempest Tour guides,Brian Morganti ,who is an astronomer too, he lives in Bernville,PA. He was telling me about this Bortle scale a few weeks ago and I sent him this article too and here's what he says about it. He told me that Tempest's storm chase Tours have been to Big Bend Nat. Park and I may get there on next May's trip, they've been chasing there a few times so I'll take my f2.8 28mm lens just in case.
You can check your own area on a Bortle world map. Here's the colour scale
http://en.wikipedia.org/wiki/Bortle_Dark-Sky_ScaleHere's the World Atlas for it. I think you can enlarge your area..
http://www.inquinamentoluminoso.it/worldatlas/pages/fig1.htmHere's what Brian said which you'll find interesting, I'm sure.
"Interesting article. Now that I've experience Bortle 2 (Part of the
Adirondacks is equal to Cherry Springs in Pennsylvania) it is hard to "go
back" to light polluted skies. Here where I live I'm about Bortle 5, very
close to Bortle 4. But there is a huge jump in stars going to Bortle 2. I
would argue a bit with Bortle 1 only being available the middle of the
ocean...certain parts of Death Valley, CA and Big Bend Ntl Park in TX are
also rated Bortle 1.