... The vertical circle (2) was used to measure the hight of the celestial body above the horizon. 3 - geometrical scheme of the Moon eclipse, which Gipparch used for valuing the distance the Earth - the Sun and the Earth - the Moon. ...
... These ancient observatory were the constructions of "horizontal astronomy", that is they marked the points of Sunrise and Sunset (they could not measure the hight of the celesting body over the horizon). ...