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Richard Walker

Spectrum and Sky

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We all know the rainbow, which is the result of sunlight (or any other light) bouncing around inside a raindrop.  The different colours return at different angles and so we see the coloured bands, like light shining through a prism.

Sunlight may also bounce round inside tiny prisms of ice.  These of course are six-sided, like snowflakes.  This can produce many different sky effects and where I live -- Cambridge UK -- the one called 'sun dogs' is quite common, in fact much more frequent than rainbows.

Most people have never seen them though, because they don't know where or when to look.

Once you have seen a thing you will probably see it again many times, even if you never previously knew it existed.  Learning makes us more aware.

Visit this site and you can find out more.  The evening sun dogs are the ones I have often seen.

Sadly there are no sun cats.


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Richard Walker

Snowflakes again

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Edited by Richard Walker, Saturday, 23 Jan 2010, 01:53

I've always thought symmetry was heart-breaking and snowflake patterns marvellous in their variety - and their temporary existence.  Bentley, the New England farmer who photographed so many snow crystals over 40 years (see earlier blog post snowflake(1)) lamented that each was unique and so beautiful, but gone forever in seconds or less.

Yesterday some of Bentley's original photos - plates I guess - were at auction and this was reported in many newspapers.  Go look



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Richard Walker

A feeling for snow

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Edited by Richard Walker, Tuesday, 5 Jan 2010, 00:05

Miss Smilla's Feeling for Snow is a famous novel.  But Wilson Bentley also had a feeling for snow and was the pioneer of snowflake photography, see


A more recent photographer of snow crystals is Kenneth Libbrech, see



These images are all wonderful.

Looking at snowflakes many have asked how each of the six arms of the snowflake 'knows' how to keep itself in symmetry.



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