Bill Walton wrote: > To get the desired accuracy the "pin-holes' themselves must be very > accurately aligned (not true if the free "pin-hole" technique is used and > the hole moved back and forth until the shadow of the gnomon is centered, > and on the hour mark, at the same time)
They would not have to be more accurately aligned than the hour line itself. In fact, you could drill a hole in the center of each hour line and use that as your pinhole. You're "on the money" when the image of the gnomon bisects the image of the sun, regardless of where those images are projected. --Art Carlson "Who knows what evil lurks in the hearts of men? The Shadow knows!"
