<P> Written records of navigation using stars, or celestial navigation, go back to Homer's Odyssey where Calypso tells Odysseus to keep the Bear (Ursa Major) on his left hand side and at the same time to observe the position of the Pleiades, the late - setting Boötes and the Orion as he sailed eastward from her island Ogygia traversing the Ocean . The Greek poet Aratus wrote in his Phainomena in the third century BC detailed positions of the constellations as written by Eudoxos . The positions described do not match the locations of the stars during Aratus' or Eudoxos' time for the Greek mainland, but some argue that they match the sky from Crete during the Bronze Age . This change in the position of the stars is due to the wobble of the Earth on its axis which affects primarily the pole stars . Around 1000 BC the constellation Draco would have been closer to the North Pole than Polaris . The pole stars were used to navigate because they did not disappear below the horizon and could be seen consistently throughout the night . </P> <P> By the third century BC the Greeks had begun to use the Little Bear, Ursa Minor, to navigate . In the mid-1st century AD Lucan writes of Pompey who questions a sailor about the use of stars in navigation . The sailor replies with his description of the use of circumpolar stars to navigate by . To navigate along a degree of latitude a sailor would have needed to find a circumpolar star above that degree in the sky . For example, Apollonius would have used β Draconis to navigate as he traveled west from the mouth of the Alpheus River to Syracuse . </P> <P> The voyage of the Greek navigator Pytheas of Massalia is a particularly notable example of a very long, early voyage . A competent astronomer and geographer, Pytheas ventured from Greece through the strait of Gibraltar to Western Europe and the British Isles . Pytheas is the first known person to describe the Midnight Sun, polar ice, Germanic tribes and possibly Stonehenge . Pytheas also introduced the idea of distant "Thule" to the geographic imagination and his account is the earliest to state that the moon is the cause of the tides . </P> <P> Nearchos's celebrated voyage from India to Susa after Alexander's expedition in India is preserved in Arrian's account, the Indica . Greek navigator Eudoxus of Cyzicus explored the Arabian Sea for Ptolemy VIII, king of the Hellenistic Ptolemaic dynasty in Egypt . According to Poseidonius, later reported in Strabo's Geography, the monsoon wind system of the Indian Ocean was first sailed by Eudoxus of Cyzicus in 118 or 116 BC . </P>

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