Rafael Soler Gaya has designed and built several robust and vandal resistant bifilar sundials. Most are in Mallorca and described in my presentation “Sundials in Mallorca” available here as a 28 MB 64 page Power Point file. https://drive.google.com/open?id=1jhijp42m2dacGNDIqg4WOx7Fyn3XKgrF
The cover picture showing the dial at Camp de Mar, Mallorca is here as a 150 kb JPG. https://drive.google.com/open?id=1OsRUKFq0ujkd2qoa528D61dF1AG-nTWD My favourite is the garden fountain bifilar. Here a water jet falling in in a parabolic curve and a chain hanging in a catenary curve form the intersecting bifilar shadows on the vertical wall. His techniques are described in the NASS Compendium V13-4 Dec 2006 and the BSS Bulletin 22 (IV) 34-37) Roger bailey Walking Shadow Designs N 48.6, W 123.4 From: César Busto Sent: September 29, 2019 8:34 AM To: [email protected] Subject: Sundial designs against vandalism (Cesar Busto) A robust and anti-vandalism solution would be to build a bifilar sundial with two vertical walls whose heights correspond to a classic bifilar . By adding an hole to the N-S wall, you could trace an analemma. César Busto --- This email has been checked for viruses by AVG. https://www.avg.com
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