Thank you, Bill, for your very kind words. I'm glad my article hit the spot for you. I'm very fond of Italian Hours - one thing a sundial does a whole lot better than a watch is to tell you how long it is to sunset.
The originator of the cone gnomon is, I believe, Javier Moreno Bores. I'd seen pictures of his dial at Genk. While working out how it must work, I realised (as he surely knows) that its hour lines are exactly the same as the half-hour lines of a conventional sundial. I also spotted that you don't need the whole cone - any conic section would be just as good. So a circular disk or ring surrounding a conventional gnomon would tell Italian and Babylonian hours on the existing hour lines. At that point, I remembered seeing somewhere a picture of a sundial with a gnomon consisting of a shiny metal tube that was bent to form both a polar gnomon and an equatorial circle. So, someone else seems to have had the idea of combining both gnomons on one dial before I did. Very sorry, but I don't know who. While thinking of other ways to realise the gnomon physically, I thought of using a CD. It turns out to be ideal, except for the hole in the middle, as its silvering helps you hold it at the correct angle. If anyone reading this is not a member of the BSS and would like a picture of my "Universal Italian and Babylonian Hours Accessory" consisting of nothing more than 3/4 of a CD, please email me off list. Please be careful not to email the whole list. Chris Lusby Taylor 51.4N 1.3W ----- Original Message ----- From: Bill CS.Com To: [email protected] Sent: Thursday, March 29, 2007 7:31 PM Subject: Article in March BSS bulletin I want to recommend Chris Lusby Taylor's article in the March BSS Bulletin on Italian/Babylonian hours and how they relate to the horizontal sundial. I had never really been interested in these hours much before, and did not understand the geometric principles involved. Chris's article took a little work for me to understand, but it was worth it, as the illustrations and text were right-on. I now understand how cone gnomons can naturally display these hours. Best of all, he describes a method for easily telling hours from sunrise, or hours to sunset, from a horizontal sundial, using just a (destroyed) round Music CD. Very clever. Chris, did you discover this method yourself, or is a modern day adaptation of a previously known method? Bill Gottesman Burlington ------------------------------------------------------------------------------ --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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