Airglow in Andromeda | JJ Modig

JJ Modig
Location of photo
ASKC Dark Sky Site
Date/Time of photo
July 21 around midnight
Canon 300d with a Canon 28-70mm lens at 28mm f/5.6. 2 minutes exposure time. ISO 1600
I was taking some star trail pictures when I noticed these weird greenish clouds. I found out the next day that it was an uncommon atmospheric phenomenon known as airglow which is caused by a chemical reaction in the upper atmosphere.