Beautiful, John!! A real piece of functional art... As I read your description, I also wondered why we haven't seen more small analemmatic dials. It (now) seems like a perfectly natural idea! When you mentioned having an attached, sliding gnomon, I had a vision of a mechanical means of placing one. I wouldn't think it would be the ideal plan for a stone dial like yours. On the other hand, it might be appropriate for a metal instrument, like one of Tony Moss's brass sculptures.
Have the gnomon attached to a sliding block, running in a slot through the dial face. Under the face, possibly within the thickness of the dial plate, run a long-pitch leadscrew, to move the gnomon north and south. If the leadscrew is cut with dual left- and right-hand threads, like a "Yankee" screwdriver, continuous rotation (in either direction) will move the carrier block out and back, linearly. Link a 12-month calendar dial face and pointer to the screw, and you have a direct setting for the date. Of course, a single thread screw would work also, but then you would have to contend with stops and the operator would need to reverse the cranking direction at the Solstices... Dave Bell 37.28N 121.97W 24 October 2002 -
