Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 7, 2025
From the use of the gnomon there naturally grew up the conception of angular measurements; and with the advance of geometrical conceptions there came the hemisphere of Berosus, the equinoctial armil, the solstitial armil, and the quadrant of Ptolemy all of them employing shadows as indices of the sun's position, but in combination with angular divisions.
For the astronomers Ptolemy Euergetes placed in the Square Porch an equinoctial and a solstitial armil, the graduated limbs of these instruments being divided into degrees and sixths. There were in the observatory stone quadrants, the precursors of our mural quadrants. On the floor a meridian line was drawn for the adjustment of the instruments. There were also astrolabes and dioptras.
Word Of The Day
Others Looking