Northern Triangle

The first thing that my eye is drawn to is the upper third of the frame, where it is pulled in by many vast colors complimenting each other. I have seen many shots like this before but yours has some highly unique color combinations I have never seen in a aurora. The form of the lines in the sky is quite nice in that it seems to move my eye in a diagonal pattern up to the top and then down to the bottom of the frame.

Now, the bottom of the frame is where I feel the image starts to fall apart. The cloud for instance in the bottom left has no real purpose for being there, it just distracts from the great yellows and greens of the aurora near it.

Next, I would say is the trees near the bottom left (I understand that they probably had to be there when you composed this) they don't really go with the brush on the bottom right which is what I find more appealing out of the two.

Overall, the bottom right brushes are placed perfectly in the frame and I kind of just want them to be the only element in the foreground minus the other brush and clouds on the left.

I hope that helps,
Cheers!