I would love to know how the Aurora knows to stop visibility at the state border.

The point of substance here is how far south Alabama is, and how many other places, sky glow aside, could experience this, if it can reach as far south as Alabama.

Alabama state tax is 4% so maybe the Aurora is attracted to low tax economies?

Longitude is not the inly factor. it has to be dark enough to see them, so the laitude matters