To go along with these, aurora light consists of emissions at specific wavelengths, and this can potentially interact with the optical system of the camera you use to produce interference patterns. If you see these patterns (which can appear as rings of light and dark around the middle of the photo) then that indicates that a good portion of the light is at least monochromatic, which very strongly indicates aurora. If you don't see them, it means nothing - your camera might just not have an arrangement that does that.