Message text written by "Istituto Nautico ARTIGLIO" >So I think that, but it's only my opinion, for gnomon should be (and were by ancient astronomers) called only vertical objects (such as obelisks) casting the shadow on a horizontal surface.<
You may be right - Sharon Gibbs (Greek and Roman Sundials) quotes a credit to Anaximander (580BC) for first setting up a vertical gnomon (at Sparta) but the term was much used later when almost all Greek and Roman dials used the point (of the gnomon) as the shadow casting element. The word gnomon then referred both to the point and to the stick/rod of which the point was a part. Hmmm, I suspect that we might wrongly be trying to attribute today's scientific disciplines to times before that was understood! Patrick
