I built this hemisherium from a clear 4" plastic Christmas ornament. The
location of the center, the radius and the circles draw was an experience
greater than one can have from looking at a model or viewing pictures.
Thank you Fer for providing the directions.
Warren Thom
On Tue, 26 Oct 2010 14:01:59 -0500, fer de vries
<ferdevr...@onsneteindhoven.nl> wrote:
Phil,
On this address
http://www.dse.nl/~zonnewijzer/hemisph.htm
you find a pocedure I once wrote to construct a hemisherium.
Best wishes, Fer.
Fer J. de Vries
De Zonnewijzerkring
http://www.de-zonnewijzerkring.nl
Molens
http://www.collsemolen.dse.nl
Eindhoven, Netherlands
lat. 51:30 N long. 5:30 E
----- Original Message -----
From: Phil Walker
To: sund...@rrz.uni-koeln.de
Sent: Tuesday, October 26, 2010 6:48 PM
Subject: Hemicyclium dials
Hi diallers,
I am considering a model cube dial with E. S and W faces, each with
a concave hemisphere on it. It would have a pin gnomon with a ball nodus
at the end, at the centre of the hemisphere. I understand that this is
based in the Greek" hemicyclium" but there.are a few 16th century cube
dials of this type in England and Scotland.
I've two questions,
What are the dial equations for the hour- and day-curves for a
hemicyclium-based dial? Do they require some spherical trigonometry?
How' in practice, could I draw/paint/scribe etc the said curves onto
the concave shapes?
Your help would be appreciated,
Phil Walker
52N2W (ish)
http://www.sundial.pwp.blueyonder.co.uk/
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