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Date: 15/04/2015

Location: Kirkeness - Norway

Camera: Canon 50D

Optics: Canon F2.8L 14mm

Exposure: 30 Seconds

Rosalie and I were staying at the Kirkeness Snow Hotel during our Norwegian holiday's in 2015 and about to go for our evening meal. This was when the evenings sky show began in the form of Aurora Borealis, so we stopped where we were and setup our tripod to commence imaging the night sky as dust gave way to a dark night sky. 

Sadly for those who chose to continue with there evening meal, natures light show stopped after about an hour and they did not see the show.

 

  

Name: Northern Lights - Aurora Borealis

Most auroras occur in a band known as the auroral zone, which is typically 3° to 6° wide in latitude and between 10° and 20° from the geomagnetic poles at all local times (or longitudes), most clearly seen at night against a dark sky. A region that currently displays an aurora is called the auroral oval, a band displaced towards the nightside of the Earth. Day-to-day positions of the auroral ovals are posted on the internet.  A geomagnetic storm causes the auroral ovals (north and south) to expand, and bring the aurora to lower latitudes. Early evidence for a geomagnetic connection comes from the statistics of auroral observations. Elias Loomis (1860) and later in more detail Hermann Fritz (1881) and S. Tromholt (1882) established that the aurora appeared mainly in the "auroral zone", a ring-shaped region with a radius of approximately 2500 km around the Earth's magnetic pole. It was hardly ever seen near the geographic pole, which is about 2000 km away from the magnetic pole. The instantaneous distribution of auroras ("auroral oval") is slightly different, being centered about 3–5 degrees nightward of the magnetic pole, so that auroral arcs reach furthest toward the equator when the magnetic pole in question is in between the observer and the Sun. The aurora can be seen best at this time, which is called magnetic midnight.

In northern latitudes, the effect is known as the aurora borealis (or the northern lights), named after the Roman goddess of dawn, Aurora, and the Greek name for the north wind, Boreas, by Galileo in 1619. Auroras seen within the auroral oval may be directly overhead, but from farther away they illuminate the poleward horizon as a greenish glow, or sometimes a faint red, as if the Sun were rising from an unusual direction. Its southern counterpart, the aurora australis (or the southern lights), has features that are almost identical to the aurora borealis and changes simultaneously with changes in the northern auroral zone. It is visible from high southern latitudes in Antarctica, South America, New Zealand, and Australia. Auroras also occur on other planets. Similar to the Earth's aurora, they are also visible close to the planets’ magnetic poles. Auroras also occur poleward of the auroral zone as either diffuse patches or arcs, which can be sub-visual.

Colours in aurora -  There are thousands of individual colours in the aurora, each resulting from a specific electron cloud energy transition of an excited atmospheric atom, molecule or ion returning toward a 'ground' (=lowest) energy state, but three are dominant. Near the lower border a green atomic oxygen emission generally dominates; at an altitude of 250 km a red emission from atomic oxygen dominates; throughout the aurora a violet emission from a molecular nitrogen ion is significant. - Written by Gary Burns.