Zhang Heng

Zhang Heng  (78-139) was a Chinese astronomer, geographer, and mathematician. He constructed a celestial globe, believing that the world was round, "The sky is like a hen's egg, and is as round as a crossbow pellet; the Earth is like the yolk of the egg, lying alone at the centre. The sky is large and the Earth small." He also created a primitive, but very fanciful . His approximation of pi was the square root of 10.

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Zhang Sui

A Chinese astronomer and Buddhist monk of the Tang dynasty, Zhang Sui (683-727), was the first to describe proper stellar motion, or the apparent motion of stars across the plane of the sky relative to more distant stars. In Western astronomy, Edmond Halley is credited with this discovery in 1718 for some stars from Ptolemy's catalogue.

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Tsu Ch'ung-Chi

Tsu Ch'ung Chi (430-501) was a Chinese mathematician and astronomer. In astronomy, he arrived at the precise time of the solstice by measuring the sun's shadow at noon on days around the solstice.

He gave the rational approximation 355/113 to p which is correct to 6 decimal places.

He also proved that 3.1415926 < p < 3.1415927

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Guo Shoujing

A paper on Guo Shoujing by Ng Say Tiong and Prof. Aslaksen, National Singapore University

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Hwa Logeng

Paper by Hwa Logeng, a great 20-th century mathematician. 

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