Posted By Ron Wodaski
I do think I see a green gradient, brighter in the lower half. The fact that the top half has a magenta cast and the lower half has a green cast makes me think you were dealing with some light pollution?
My adjustment is attached. I used Color Balance in Photoshop, and I added a touch of green to the top half, and subtracted a significant amount of green from the lower half (and did a little red/blue balancing while I was at it.)