Interesting one Gordon... you know, I bet that many a condition has to be taken into account about what colour it really is in a small scope! I suppose atmospheric conditions, while changing night to night, also differ upon location on the globe! Florida may have more air pollution, or the opposite because it is close to a clear ocean. We on the other hand have to contend with SW winds probably blowing mist high into the atmosphere here, but the cold air ensures the air is clean!
This is an interesting one!
But I'm going to stick with blue!!!
Seanie.