Dear Mike,
No, I don't believe this to be off subject. It would seem that something on this order could be done by a degree of spacial filtering. From my scant readings regarding 3 dimensional holographic methods it would seem possible to create such a gnomon that would cast any kind of shape we would like, even at a greater distance than normal. Even a simple spacial filter, not involving holography should at least be able to restrict the angles of light passing around the gnomon and so increase the length of the umbra, providing a clear shadow much further away from the gnomon. We need some experts to think about it awhile maybe. Hmmm, dithered? I guess using a vibrating gnomon to modulate the light and then demodulated at the surface might do something, but not visually I don't think. Does anyone have some better ideas in this area? Edley McKnight [43.126N 123.357W] > Accurate Diaists , > > Maybe this is off subject... but, is it possible to build a "dithered" > gnomon so that it could minimize the prenumba (<- spelling?). Or some > other shape that produces a more finite edge. > > > Best regards,
