With all this talk about mirrors, I'd like to mention a solstice/equinox project that Kate Pond and I recently finished. Kate was commissioned to make a sculpture at a nearby meditative labyrinth, which is 70 feet in diameter. The task was to use sunlight to note passage of the equinoxes and the winter solstice. I helped as the math consultant.
Cylindrical focusing mirrors were place atop 2 poles spaced about 35 feet apart, each projecting a focused "line" on the ground. The path of these lines vary from day to day, but, at solar noon on the equinoxes, the lines briefly form a cross at the center of the labyrinth. A second set of mirrors does the same thing at Solar Noon on the winter Solstice. We calculated and set the placement of these mirrors in mid-September this year, and they worked bang on the dot, both at the equinox, and the recent solstice. Pictures can be seen at Kate's site: www.vermontsculpture.com/KPpages/KP_events.html Bill Gottesman Precision Sundials, LLC Burlington, VT
