Etruscan Vase during Venus Transit

At sunrise during the transit of Venus on June 6, 2012, there were not only distortions of Sun and Venus visible as well as the Green Flash, but there were also several observations of the so called Etruscan Vase.

As weather forecasts for Germany´s sunniest island, Fehmarn in the Baltic Sea, were most favorable for that day, Jens Hackmann flew there from the bad weather of his home town Bad Mergentheim. Just after sunrise at 4.41 hours, he observed the mirage effects mentioned above not only on Sun and Venus, but also on a passing ship. And only a few moments later the Etruscan Vase phenomenon appeared, an upside-down mirage of the sun which appears in most cases above a water surface (more pics and film).

Thomas Stemmler photographed the transit of Venus at beach on the Baltic Sea near Dahme and could shot mirage effects and the phenomena of Etruscian vase also.

This strange effect is caused by the refraction of sunlight together with a lower mirage and appears when a layer of cold air is positioned over a warm water surface. The lowermost air layer, which is heated up by the warm water, has a lower refraction index than the air at the level of the eyes of the observer. Sunrays hitting this layer in a very sharp angle can be reflected totally. So the observer does not only see light coming directly from the sun, but also light that had been reflected by the warmer and less dense layer of air directly above the water. The rays coming directly from the sun let the sun appear totally normal. But as our brains are not programmed for totally reflected sunrays, they extrapolate them lineally. This makes us see an upside-down reflection of the sun beneath the real sun which changes due to the angle of incidence of the light and thus with the sun elevation.

This phenomenon reminded the science-fiction-author Jules Verne of a paunchy Etruscan Vase standing on a pedestal, so he coined this term for the phenomenon.

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Posted on July 1, 2012, in air mirages, astronomical phenomena, green flash and distortions of sun and moon, observations and tagged , , , . Bookmark the permalink. 2 Comments.

  1. What a coincidence: on the very day of this posting I was finally closing in on the actual origin of the “Etruscan Vase” term for this kind of mirage. I had found out a while ago that it was apparently Jules Verne who used it first in his “Rayon Vert” when talking about the setting Sun prior to a green flash: see http://home.arcor.de/tse2008/omega.html (links at the bottom). But why would he chose this expression? Now on July 1 I joined a tour of the Antikensammlungen of Bochum University in Germany which includes some spectacular vases – and I learned that the director is a leading expert on precisely this topic. Today she told me that in the 19th century “Etruscan vase” simply meant “Greek vase” because those were mostly dug out in Etruria (roughly Tuscany) in Italy these days! Still I would argue that we should stick with the ‘Etruscan’ adjective as it sounds more dramatic. As is the phenomenon we use it for.

  2. I saw a rare rainbow column caused by the sun setting into itself, an inversion layer, where the inverted sun was on top. Extremely clear sky, no particulate matter except the cloud above me. It stalled in place as I approached I could see the mechanism inside a few 3/4″ drops radiating their color according to their position in the column, violet on far left within arm’s length! It was like a holographic image, transparent, 3D, Just standing there, waiting for me. The 75′ I walked up to it lasted 2 minutes before it receded with the rain into the trees not until the colored lights recombined into liquid golden white sparkling mass of drops all around me. please call Roger Llamas 7078872190

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