Aurora Corona

When the northern lights are really strong, you might be lucky enough to see them at their zenith, overhead like a corona. The picture shows the beginning of a corona last week.

An aurora corona is a spectacular form of aurora that occurs when you are directly under the magnetic field lines.

It looks as if all the light rays are radiating from a single point high in the sky (the zenith).

Why? It's a perspective effect, just like when parallel train tracks appear to meet on the horizon. In reality, the aurora rays are parallel and follow the Earth's magnetic field, but from the ground they appear to form a "crown" (corona in Latin).

Cabin Aurora

A week's stay in the family's mountain cabin where the starry sky is very dark. One night the northern lights played fantastically beautifully and went high up in the sky above the cabin. The Big Dipper is seen in the middle of the picture, upside down. It almost forms a corona of the northern lights just above. Earlier in the evening I was able to witness a corona right in the zenith, pictures will come later.

 

Aurora Show in Stockholm

Last night, nature put on a fantastic spectacle! For being in the Stockholm area, this was really nice, even the northern lights at zenith. The northern lights, or aurora borealis, are a light phenomenon that occurs when charged particles from the sun collide with gas atoms in the Earth's atmosphere. It is mainly visible in the polar regions (such as northern Sweden, Norway and Iceland) between September and March, often as dancing green, purple or red lights at an altitude of 80–500 km.

Colors: Yellow-green is most common (oxygen at an altitude of 100–140 km). Red and violet tones also occur, depending on the type of atom that collides with the particles.

Shape: They can look like arches, curtains or rays dancing across the sky.

Origin: The northern lights are caused by geomagnetic storms that affect the Earth's magnetic field.