Aurora Borealis lighting the skies over a frozen Marsh Lake, near Whitehorse in the Yukon. The green glow really did make it quite light even at 2 in the morning. Camera coped well with the low temperatures (about -25 degrees C)

Started off with the Green Layer

worked on the neutral one thne the black

enhanced some of the stars using the sponge tool whist using an unsharp mask within the LAB lightness layer, lastly added a new layer with a colour gaussian blur @25%

I think that cropping the sky is not that bad because there was too much sky in your photo IMO, and I just lightened the photo a little.

this is my very first workshop here, I hope you like it. :-)

Nelly