2005 - 2018
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[2014] Nederlands Tijdschrift voor Natuurkunde 80, 253 (Translated from Dutch)
G.P. Können

A ‘broken rainbow’ teaches us that seawater is salt – in the same way that the Venus rainbow once taught us that the cloud drops on Venus are sour.



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[2013] Terschellinger Diary 2013/01
G.P. Können
Sun-and-drops make a rainbow; sun-and-ice a halo. This somewhat unknown, but beautiful ‘little ice brother’ of the rainbow on the sun side of the sky appears more often than generally thought.

 
[2012] Announcement
G. P. Können

The popular articles at this page are also available from http://wpshetgooi.nl/gunther_konnen_2.htm.


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[2011] Terschelling Diary 2011/01
G. P. Können

On 12 November 2010 we experienced a spectacular storm surge which caused the Terschelling port area to be flooded. Supported by some photos we provide this high tide ‘with a face’, that is: we lift the surge above the domain of bare numbers. But it is also indicated how rare such an event is and how much worse it can be.


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[2009] Terschelling Diary 2009/1
G. P. Können

There exists a first and second rainbow, but the real third rainbow does not show up in Nature. Or maybe still? In any case there are rainbow exotes and other weird rainbow forms. And the roundness of the rainbow discloses us something about the shape of a raindrop.


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[2008] Terschelling Diary 2008/1
G. P. Können

The bright star Algol is the prominent exception of the seemingly never-changing  nocturnal sky, as it looses regularly no less than 70% of its brightness. The phenomenon lasts only a few hours. Events occur with intervals of three weeks. Surely one of the best objects in the celestial sky!


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[2008] Terschelling Diary 2008/2
G. P. Können

Everyone knows from own experience that the climate of an island differs from the mainland. But how true is it? In the weather statistics the differences are small. The solution to the paradox is that the largest differences occur during pronounced but rare situations, like during fine summer days.


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[2007] Terschelling Diary 2007/2
G. P. Können

The setting sun seems enormously swollen up, but that is just an optical illusion. Also it shape is quite flattened. That is real, but in reality the flattening is even stronger: turn your head and the sun becomes even more cigar-shaped. On the dunes sunset occur about a minute later that on the beach - easily noticeable, as people standing on the beach start to turn home before your sun has set!


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[2007] Terschelling Diary 2007/1
G. P. Können

If you know about them, you can't miss them: cloud streets. In particular over small elongated islands, they can remain for a long time at a fixed position. It is surprising that even locals are often unaware of this easily-observable phenomenon, while it also has escaped for long time the attention of professional meteorologists.


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[2006] Terschelling Diary 2006/1
G. P. Können

The last limb of the setting sun turns from reddish to grass-green. From a beach this so-called green flash is more often visible than generally assumed. The sun has to be bright when he sets. The recipe is: keep watching, even if you think your are too late - suddenly you see it happen!