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Message-ID: <[EMAIL PROTECTED]>
Date: Thu, 03 Sep 1998 21:01:55 +0200
From: "fer j. de vries" <[EMAIL PROTECTED]>
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To: [EMAIL PROTECTED]
Subject: Re: Shadow Engineering
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Ben Hoffmann wrote:
>
> Hello,
>
> I have many questions about sundial shadows. Hope this is interesting stuff.
> General issue is how to design the sundial so that it is most easy to read.
> This involves some engineering, and also some human perception issues. These
> are posed as open ended questions - I don't really expect answers - but many
> thanks in advance for your thoughts and comments.
>
> 1)
SNIP...
> 11) Inverse problem - same issues but using a point of light rather than a
> shadow to mark the time.
>
> Thanks for your comments!
> - Ben Hoffmann, Minneapolis, MN USA
Hello Ben Hoffmann,
About these subjects read what is written in
Sundials Australia
by Margaret Folkard and John Ward.
ISBN 0 646 27581 X
They did a lot of experiments with shadows on a sundial.
In the book there are 19 pages, titled :
Blackness and Sharpness of Shadows.
Fer de Vries, Netherlands.
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