Observation by Alan C Tough: April Aurora

Uploaded by

Alan C Tough

Observer

Alan C Tough

Observed

2021 Apr 17 - 23:05

Uploaded

2021 Apr 21 - 20:50

Objects

Aurora

Equipment
  • Canon EOS 5D Mark III DSLR
  • Sigma EX DG 20 mm lens
  • Manfrotto tripod
Exposure

20 seconds @ f/3.2, ISO-3200

Location

Hopeman, Moray, Scotland

Target name

Northern Lights

Title

April Aurora

About this image

A wide range of colours are revealed in this auroral display:

Green shading to red above is caused by the excitation of Oxygen atoms at a height above 100 km.

The purple colouration at the top is the result of an enhancement of the emission from ionized Nitrogen molecules when they are exposed to sunlight or bright moonlight. 

If the incoming particle beam has sufficient energy to penetrate the atmosphere to below 100 km, excitation of Nitrogen and Oxygen molecules produces a red lower border.

The yellow colour is due to the intensity of the display and is a mix of the green and red emissions.

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