Quiet aurora arc - 7.10.2015 at 21.45 Tuusula Observation number 43643

Visibility II / V

Pekka Manninen

Based on the predictions, I went to see if repos would show up. The beginning was faint, but soon a clear arc appeared on the horizon. I was already changing places when the gauze running through the top of the sky brightened and a clear Korona appeared there.

When I changed places after that, the sky had time to go to the cloud.

This description has been automatically translated from Finnish. Click here to see the original text.

5 7

Additional information

Aurora brightness
- Dim auroras
Colors with unaided eye and other features
- Green auroras
  
  Green, seen with the naked eye, is one the most common colors of the aurora. The green color is derived from atomic oxygen.
  
  Green auroras. Lea Rahtu-Korpela.
  
  Green auroras. Photo by Juha Ojanperä.
- Violet auroras
  
  Usually in Lapland or even in the south you can see purple auroras in stronger aurora shows. The most common color in auroras along with green and red.

Observed aurora forms
- Band
  
  Bands are usually narrower, more twisty at the bottom, brighter, and more active than arches. Bands usually develop from arches.
  
  Bands can form J and U shapes, sometimes even full spirals. The corona can also arise from bands. Bands are a fairly common form of aurora.
  
  Aurora band. Photo by Merja Ruotsalainen.
  
  Aurora band. Photo by Matias Takala.
  
  Aurora band. Photo by Lea Rahtu-Korpela.
  
  Aurora bands. Photo by Lauri Koivuluoma.
  
  Aurora band. Photo by Matias Takala.
- Corona
  
  CoronaA corona is a hand fan shaped structure, it usually forms south of the observer's zenith, most commonly consisting of rays or bands. The corona is usually the most beautiful part of the aurora show. It is bright and active, but on the other hand also short-lived.
  
  Aurora corona. Photo by Anna-Liisa Sarajärvi.
  
  Aurora corona. Photo by Merja Ruotsalainen.
  
  Corona formed from bands. Photo by Markku Ruonala.
  
  Aurora corona. Photo by Tapio Koski.
- Arc
  
  ARC The arcs are wider than the bands and do not fold as strongly. The arcs are normally neither very bright nor active.
  
  The arc is probably the most common form of aurora. When aurora show is a calm arc in the low northern sky it often doesn’t evolve to anything more during night. In more active shows the arc is often the first form to appear and the last to disappear.
  
  The lower edge of the arc is usually sharp but the upper edge can gradually blend into the background sky. As activity increases rays and folds normally develop, and the arcs turn gradually into bands.
  
  An aurora arc runs across the picture. Vertical shapes are rays. Photo by Atacan Ergin.
  
  Aurora Arc. Photo by Mauri Korpi.
  
  Aurora Arc. Photo by Anna-Liisa Sarajärvi.
  
  Aurora Arc. Photo by Matti Asumalahti.

Send a comment

Comments are checked and moderated before publication If you want to contact the observer directly about possibilities to use these images, use the Media -form.

Newest observations

Contact information

Quiet aurora arc - 7.10.2015 at 21.45 Tuusula Observation number 43643