I decided not to show a full-on star trail shot here, because the streaks completely overpowered the subtle green hues in the night sky. Instead, I calculated which images to use, having their distance grow exponentially to lead into (or away from) a solid pattern. I then picked the closest image to the equation that was visually pleasing, and stacked the images together using the "lighten" blending mode in Photoshop.
Seven shots in total were used, and the aurora fell in just the right places to leave the center of the spinning stars clearly visible. (although, it's us that are spinning - someone always corrects me!) I've just printed this as a 32"x20" canvas and it looks stunning, the first of many prints I make from my adventures in the Yukon.