shadowbands

Shadow bands on arctic ice

Like announced in our travel report for the solar eclipse 2015,  we have cut another video wich shows a very hard and rare to observe phenomenon. It´s called “shadow bands” and is only visible for a minute before and after the totality of a solar eclipse.

We (Martin Rietze and Michael Risch) have seen several total solar eclipses but we never paid attention to this special phenomenon because normally it needs special efforts to make it visible. In the few minutes around totality we are always totally busy and never had the time to place a bed linen on the floor and to take care for an additional video camera a.s.o. In Svalbard we also didn´t plan to have an additonal eye on shadow bands, but then, shortly before totality, the effect jumped in our eyes so strong that we were totally astonished.

Please see here a short but uncompressed scene from our video that shows the very fast “rays” (bands) clearly. At the end of this news posting you see the whole video on Youtube, because of the Youtube compression the effect is not as strong as in the original movie.

What are “shadow bands”?

It was fascinating to see how the long shadow bands moved from left to the right very fast. Its comparable to the shadows of waves that you see on the ground of swimming pools – but much faster. Shadow bands during a Solar Eclipse have a similar cause as the shadows on the ground of the swimming pool. The different, moving layers in the air ocean above us are affecting light rays like water does. Only when a very small beam of light penetrates these moving layers, as it happens during a solar eclipse, it is possible to see their flying shadows on the ground. The more uniform the colour of the ground is, the better they are visible. A very detailed explanation can be found on the website of Wolfgang Strickling: www.strickling.net/shadowbands.

How the video was generated

In the Arctic, on Svalbard, the ground is pure white from snow and ice. It happens very rare that Solar Eclipses take place in such regions. Furthermore the sun was very low over the horizon so that the light had to travel through thick atmospheric layers. Additionally the seeing was really bad. Alltogether, these have been ideal conditions to see “shadow bands”!

After we were very much surprised by this phenomenon during the minute before Totality we decided to change our plans and switch a Canon EOS 6D with 24mm Wide Angle lense to video mode. This way we recorded the movie with an unusual strong backlight that shows how the whole ground seemed to move like a fluid with waves that have been centered to the sun.

Unfortunately the online version of the video does not look as dramatic as the reality was, because of the Youtube compression. Anyway we hope that you get a glimpse of our fascination for this natural wonder.

Posted in AstroSolar.com News.

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