I try to write some reasons for which I think that the Egyptians has never used the obelisks as sundials 3000 years before Greeks .
Herodotus (484-424 B.C.) is the first author that makes mention of the gnomon with the meaning of sundial : "Greeks have learned from the Babylonians the polos and the gnomon, as the twelve parts and day" (Hist. II). The invention of the first sundials is often attributed to the philosophers Anaximander (610-545 B.C.) and Anaximenes (586-525 B.C.) but certainly the gnomon, simply made by a pole vertically fixed to a horizontal plane, was known and used by he Babylonians. According to some modern researchers (for ex. Szabo, Maula in "L' astronomie chez le grecs") it is almost sure that the gnomon was not used in the period 3-400 B.C. as element of a sundial but only as calendrical instrument - to find the beginning of the different seasons - and as astronomical instrument for the determination of the days of the solstices and of the equinoxes, of the length of the inter-solsticial arc (and therefore of the ecliptic inclination) and of the gnomonic equinoctial ratio (ratio between the gnomon's height and the length of its shadow at noon on the equinoxes) that was used in antiquity instead of our modern "latitude" (as in Vitruvius). Therefore the gnomon did, some century before our epoch, the same functions of the great camera obscura sundials built, as great astronomic hinstruments, in the XVII century. Almost certainly the sundials of Anaximander and Anaximenes, built for different purposes, could only mark the noon or the passage of the Sun on the Southern meridian . Gianni Ferrari 44° 39' N 10° 55' E Mailto : [EMAIL PROTECTED] -
