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Perspectively broken shadow

When there are swelling cloud parts on the surface of an unbroken cloud cover, it sometimes can happen that the shadow of a pole projected onto this cloud cover appears kind of broken. I could observe such a shadow broken perspectively on August 18, 2007, at 18.15 hours CET on the top of Mt. Wendelstein (1835m), when the shadow of the transmitting aerial of the Bavaria Broadcast fell upon such a cloud cover, surrounded by a glory which appeared three-dimensional.

Author: Claudia Hinz, Brannenburg, Germany

Alder corona with iridescence and cloud rays

The 27th of March was in a manner of speaking one of our first warm days this year. Owing to the long and cold winter together with the abrupt change the plants exploded into life and produced a very strong pollen concentration in the air. The humidity was very low and so the resulting pollen coronae stood out against the dry sky. The coronae originated from from alders which are very common in the area (Barsinghausen, near Hannover). Hazel were also flowering at that time but would have made a different form of corona.

That day Reinhard Nitze took very unusual pictures of the alder coronae. On the one hand the coronae were intense but appeared together with another phenomena, e.g. with iridescence clouds or cloud rays. Sometimes, however, Reinhard saw them “undecorated”.

Shadows during the annular eclipse

Günther Können took these pictures in Madrid during the annular eclipse of 3rd Oct 2005. They are solar images projected onto three mutually perpendicular surfaces: one horizontal and two vertical. During the annular phase (right hand image) the solar images were ellipses, with their long axes oriented in different directions on the two walls and the steps and ground. This was not unexpected. However, in the picture showing the pre-annular phase, one notices that the sun crescents on the ground and steps comprised the more pointed part of the ellipse, whereas on the walls they are the more rounded part of the ellipse. The key is in the third picture, where the shadow of the roof overhang kinks from one projecting plane to the other. In hindsight, all of this is understandable, but I have never seen a comment on this ‘solar image puzzle’.

Shadow Trident in Clouds

On April 15, I had the chance to observe a shadow trident above the pylon of our wind gauge on Wendelstein mountain (1835 m). When an observer is situated in the shadow of the pylon itself, there are regions above the pylon from where no light reaches the observer`s eye. If there is a “screen” of water droplets (clouds) or ice crystals (diamond dust) above the pylon, these regions can become visible as shadow rays. In my observation, cumulus clouds repeatedly passed rapidly over the top of the mountain and the shadow rays were briefly visible several times.

Posted by Claudia Hinz