[citivolus (Ric)]

Originally Posted by AJames

Interested readers here should download the probably definitive ADS pdf article written in 1960 by Bart Bok on this very subject, including a few maps. Ie. http://adsabs.harvard.edu/abs/1960JRASC..54..257B

Thanks for all that, it was interesting to read through. I wonder what good dark sky sites were excluded at the time due to remoteness, which today might be looked upon more favourably?

One more graphic, to make it easier for those who like to overlay additional data. This one was done using interpolation of the climate station data to create a 3 arc minute grid, allowing a higher level of detail to show through in the areas in which it was available.