Well done, Fer and Joel. I'm sure Kate Pond's sundial was the one I remembered. Strangely, though, I now realise it almost certainly doesn't have any hour lines on the horizontal base, so misses the possibility of showing Italian Hours.
Kate: what we're discussing here is that, if you put conventional hour lines on the base of your Skywatch, the polar gnomon would show conventional hours, while the edges of the circle would show Italian and Babylonian hours on the same lines, but with all numbers doubled (i.e. read, say, 3:15 as 6:30). Also, incidentally, you could put dates along the polar gnomon and use the shadow of the circle on it to indicate the date. Best wishes Chris ----- Original Message ----- From: robic.joel To: fer de vries ; Chris Lusby Taylor ; Bill CS.Com ; [email protected] Sent: Friday, March 30, 2007 9:47 PM Subject: Re: Article in March BSS bulletin You can see a photo on: http://perso.orange.fr/cadrans.solaires/cadrans/cadran-kate-pond.html Best regards, Joël 48°01'25'' N, 1°45'40" O ---> http://www.cadrans-solaires.fr/ ----- Original Message ----- From: fer de vries To: Chris Lusby Taylor ; Bill CS.Com ; [email protected] Sent: Friday, March 30, 2007 8:39 PM Subject: Re: Article in March BSS bulletin Chris, You wrote: 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. Could it be the (small) sculpture by Kate pond? Diameter about 4.5 inch. Named Skywatch. Coyright Kate Pond. An advertisement is in Compendium vol. 2 nr. 4 december 1995, page 26. Think for the copyright. Best wishes, Fer. Fer J. de Vries De Zonnewijzerkring mailto:[EMAIL PROTECTED] http://www.de-zonnewijzerkring.nl Eindhoven, Netherlands lat. 51:30 N long. 5:30 E ----- Original Message ----- From: Chris Lusby Taylor To: Bill CS.Com ; [email protected] Sent: Friday, March 30, 2007 12:40 AM Subject: Re: Article in March BSS bulletin 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 -------------------------------------------------------------------------- --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial ---------------------------------------------------------------------------- --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial ------------------------------------------------------------------------------ --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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