Active aurora band - 7.10.2018 at 20.22 - 8.10.2018 at 00.40 Tampere, Terälahti Observation number 87817

Visibility Unclassified

Sirpa Pursiainen

Just two weeks ago, I deleted pictures from tonight. Luckily I had uploaded one picture to Facebook that also had dunes .... one more time I have to go through all the memory cards to see if there is more.

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

8 7

Additional information

Aurora brightness
- Bright auroras
Observed aurora forms
- Dunes
  
  Dunes
  
  The dunes are a dim and very rare shape that has so far been associated with the aurora visible in early evening.
  
  Aurora dunes can be most easily confused to ribbons on lower clouds. In order to fill in the description of the phenomenon, a striped pattern formed by parallel lines must also appear in the aurora. The stripes are most easily recognizable right at the front edge of the aurora but they may also occur among the rest of the aurora.
  
  The dune auroras are visible as a parallel striped float. Photo by Tapio Terenius
  
  Raidallisen dyynilautan reunassa voi toisinaan olla voimakastakin aaltoilua.
  
  There can sometimes be strong ripples at the edge of a striped dune float. The rippling of the edge of the dune float can vary from minor to large (pictured). Photo by Pirjo Koski
- Veil
  
  Veil
  Veil is the most bland and very common form of aurora. It usually covers its homogeneous dim glow over a wide area of the sky at once. Most often, the veil is seen in the calmer and quiet phase of the night after the aurora maximum as a background for other forms. The veil can also occur alone and in that case it will be quite difficult to reliably identify as an aurora, especially at a observation site which has a lot of light pollution.
  
  A similar glow of light can also be caused by airborne moisture, smoke, or a very thin layer of clouds that reflects the light that hits them. However, clouds can also be used to identify veil, especially if the middle or upper cloud appears dark against a lighter background, then it is very likely to be aurora veil if the brightness of the background sky is not due to the rising or falling Moon or Sun. When photographing, very long exposure times usually reveal the green colour of the veil auroras.
  
  Veil and rays. Photo by Esa Palmi.
  
  Red aurora veil. Photo by Marko Mikkilä.
  
  Veil. Photo by Milla Myllymaa.
  
  Aurora veil that changes color from green at the lower edge through purple to blue at the top. Photo by Jaakko Hatanpää.
  
  Dim green veil. Photo by Jarmo Leskinen.
  
  Radial aurora band surrounded by veil. Photo by Jussi Alanenpää.
- 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

Active aurora band - 7.10.2018 at 20.22 - 8.10.2018 at 00.40 Tampere, Terälahti Observation number 87817

Dunes