A red and green aurora, from home on Oct 1, 2013, looking southeast. The green arc was obvious but the red was invisible to the naked eye – it only showed up on camera and this was a red-sensitive modified Canon 5D Mark II. This is also looking southeast, away from the main auroral band to the north. This was 30 seconds at ISO 800 and with the 24mm lens at f/2.2.
The Amazing Sky 