>>>that's why such a gnomon might be terminated with a knob or ball. >>> >>>My questions are, if the gnomon ends with a ball would you measure the >>>length of that gnomon to the center of the ball or use the overall length? >>>Would the shadow's tip be easier to determine with one scheme over the >>>other?
My thought on this is that the ball should be at least big enough to cast an umbral shadow. With a smaller gnomon light from one edge of the sun is able to illuminate where the other edge is blocked. You would measure to the center of the ball because that is what casts the center of the shadow. Peter -- Peter Hirtle [EMAIL PROTECTED] Seattle, WA.
