Full spectrum illustrates nicely how visible and infrared aurorae correlate to each other. It seems that infrared emissions lie slighly below the green ones, and are probably in the same region as the visible red emissions. Due to the infrared leak of the blue channel, this results in a white northern light in full spectrum. As a bonus, the nothern lights near the horizon become purple, because the atmosphere absorbs most visible light – so there is actually a bit of pure infrared hidden in this photo.