Düsseldorf Leaning Tower and other Shadow Plays

On November 16, 2010, Hans Juergen Heyen had a rather “spooky” day in Düsseldorf. “A short time after noon I took a walk along the river Rhine and wanted to shoot some photographs. In the beginning, the sky was completely clear except some mist, but at about 14 hours some ragged clouds came up which lowered down to about 100 metres above the ground. The clouds were followed by a mixture of fog, sunshine and clouds which in this area (Lower Rhine region, about 45 metres above sea level) is very uncommon. Also the frequent change between a nearly closed layer of stratus clouds and blue sky was rather strange.
A great help for evaluating the situation was the Rheinturm, a TV tower which is about 240 metres high and has a restaurant with an inclined bank of windows at about 180 metres. This tower disappeared and reappeared between the fog and clouds causing some shadow plays and reflections which were rather irritating for the observer. Sometimes even phantoms of the tower appeared. The tower quasi became an actor in this weather phenomenon. Some time ago, I witnessed a similar phenomenon at the same place, which at that time had turned out considerably fainter. But this time, the phenomenon lasted for about two hours. It just seemed as if the Cllerk of the Weather had been sitting in a pub in Düsseldorf Altstadt and lost the control about his remote weather control while drinking the famous Altbier, a very popular kind of beer in Düsseldorf. For people interested in weather phenomena, it was a really gorgeous afternoon”.

Two main phenomena were visible: When the sun was beside the tower, it caused reflections in the bank of windows around the tower restaurant projecting shadow rays onto the wall of fog. This was a kind of reflected anticrepuscular rays (1–2–3–4).

Later, when the sun was almost behind the tower, another strange shadow play became visible. Contrary to what is usual, the shadow of the tower was not on the side of the tower which points away from the sun, but in direction towards the sun. This was because the observer was now postitioned in the diffuse shadow of the tower. Normally he should now see the shadow behind himself on the ground. But as the droplets of the wafts of mist formed a kind of screen in front of and below the top of the tower, the shadow of the tower was now displayed on the fog.

Sometimes the shadow was displayed on several layers of fog forming multiple images [1–2].
When the sun is positioned directly behind the tower, only the upward projection of the tower top is visible, being cast upon ragged clouds above the tower by the low autumn sun. More pictures 1–2–3–4–5–6