On Thu, 2 Mar 2000, Claude Hartman wrote: > Another example was shown at the Reutte, > Austria, sundial competition in 1998. > This was submitted by Rafael Soler and > called a "Bi-Filar" sundial. It marked > time by the intersection of the shadow > of a horizontal disk and its vertical > support rod. > > A larger photo is in my report > of the Reutte competition at the 99 NASS > Conference on the NASS web site:
http://www.sundials.org/conference/confpix/c-soler_m1.jpg This is a very interesting dial design! As Claude described it, the disk-shaped "hat" and the vertical shaft form the two edges of a bifilar style. I can see how this could also be implemented as a single vertical pole, with an overhanging "roof", the roof edge and pole casting their shadows on the back wall of a porch or verandah, either vertical or sloped as is Soler's dial plate. Fer or Gianni: Would it be possible to include a more general sort of bifilar dial design in your program(s)? Fer's Zonwvlak computes bifilar designs, but assumes the threads are parallel to the X and Y axes, and (I think) intersect the Z axis. Gianni's only accepts a single thread, but allows it to be defined by two arbitrary (XYZ) points. A combination of the two would be really, really nice!! :{) Dave Bell W121.9N37.3
