1. Graphic showing color and source of emissions at various altitudes 2. Emission spectrum of Atomic Oxygen 3. Emission spectrum of Molecular Nitrogen Source for 1 - https://www.flickr.com/photos/11304375@N07/2844511020/in/photostream/ Source for 2 and 3 - http://ffden-2.phys.uaf.edu/webproj/212_spring_2015/Joyce_Dustin_Demientieff/joyce_dustindemientieff/colors.html
https://cdn.fosstodon.org/media_attachments/files/112/425/110/089/539/087/original/b686c70d12c70886.png