- 600 BCE in Egypt
'Merkhet', Ancient Egyptian astronomical timekeeping instrument, bronze with hieroglyphic text inlaid with electrum metal, fitted with replica plumb bob, 600BCE. Inscription indicates it was the property of Bes, son of Khonsirtis (Khensardais var.), an astronomer priest of the god, Horus of Edfu in Upper Egypt. Used to layout axes of buildings and to determine the hours of the night by observing the passage of selected stars across the north-south meridian.