Carl Størmer and the Northern Lights

By Arne Langleite

The first photograph of the northern lights was taken as early as 1892 by the German Martin Brendel. For scientific use, the first photographs were not clear enough, due to the long shutter speed required to capture the phenomenon. The photos were taken at night, and the northern lights were blurred and indistinct.

Carl Størmer (1874-1957), who had been an enthusiastic photographer since his student days in Kristiania in the 1890s, had the idea of ​​using triangulation to determine the height of the northern lights above the Earth's surface. Such knowledge would be essential for understanding the phenomenon better.

There were several people interested in finding a solution to this. Physicist Ole Andreas Krogness, who was the manager of the observatory at Halddetoppen near Alta, had developed a camera that took six pictures on the same plate using a movable lens, so that several pictures could be taken in rapid succession.

Størmer found a solution to the last problem with the camera, which was to get enough light to take a sharp picture of moving shapes. He used a small lens from a children's film camera from the German manufacturer Ernemann. This camera became an important instrument for northern lights research also internationally, 300 cameras were sold to researchers all over the world.

With the camera technology in place, Størmer established stations at least five kilometers apart, which kept in touch by telephone. When an interesting northern lights phenomenon appeared, the photographers at the different stations took pictures of the same northern lights, at the same moment. In order to be able to compare and make calculations, they made sure that the same star or constellation was placed in the middle of the picture.

Using calculations that could be made based on the images, it was eventually established that the average height of the aurora borealis is just over 100 km above the Earth's surface. (However, observations were made down to 71 km and of sunlit auroras up to 1000 km.)

In addition to establishing the height of the aurora borealis, the large amount of photographs provided the opportunity to establish different types of aurora borealis. These were used, for example, in an aurora atlas produced in connection with the second International Polar Year in 1932-33. The atlas was distributed to collaborators in, among others, Canada, the United States, the United Kingdom and the Netherlands, and also contained procedures and conventions for photographing the aurora borealis in a way that would yield good results for later calculations.

Størmer took the first photographs of the northern lights in 1909, and continued to survey them until his death. A large number of photographs were produced, which provided the basis for research by both Størmer and others. Most of the images have been lost, but at The Norwegian Museum of Science and Technology we still have a few hundred examples of Størmer's work.