A

• Born in England.
• His Transit Circle is still the official reference for longitude zero.
• Through his influence, Greenwich Mean Time became the standard for Britain, and, later, for the world.

Al-Sufi (903-986)

• Born in Arabia.
• He integrated Ptolemy’s star catalogue with Arab star tradition and terminology.
• He defined boundaries for the constellations.

Eugenios Antoniadi (1870-1944)

• Born in Turkey.
• He drew the best map of Mars of his day and modified the names of the planet’s features.
• He studied Mercury and Venus, but drew some incorrect conclusions about them.

Aristarchus (ca. 310 BCE – ca. 230 BCE)

• Born in Greece.
• He was one of the first to maintain that Earth is in motion around the Sun.
• He stated that the Moon shines by reflected light.

Aryabhata of Kusumapura (476-???? CE)

• Born in India.
• He made calculations of the sizes of the orbits of the Moon, Mercury, Venus, Mars, Jupiter, and Saturn.
• He devised a procedure for calculating the magnitudeand the duration of an eclipse.
• He believed that Earth rotates and that Earth and the planets orbit the Sun.