In the few books I have on sundials, they all seem to depend on either the sun's shadow or reflection. I was searching patents (class33/269=30 patents '76-'95, class 356/130.01=2 patents '76-'95) and found a few that used cylindrical plastic/glass lenses. Does anyone know about dials that are very accurate (about 1 second of time) and/or that use actual lens type optical systems? I would think there is something between a simple shadow dial and a surveyers transit.
I have designed a vertical South facing noon mark that tells PST (and in the summer PDT) within about 12 seconds of time. I am looking for a more accurate dial (rather than a noon mark. Have Fun, Brooke
