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: [email protected] 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/ ------------------------------------------------------------------------------ --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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