FREE ESSAY ON SHEN KUA

SHEN KUA

Astronomy 201
Astronomer, Shen Kua
Shen Kua was born in China in the year 1026. Shen Kua was born to Shen Chou and his wife
Hsa. His family had an unbroken tradition of being civil servants. Thus his father was a
local administrator of many posts from Szechwan in the west to the international port of
Amoy. At Sixteen years old Shen Kua left his home to travel with his father from post to
post. While traveling with his father, Shen Kua learned the responsibilities of a local
administrator. These responsibilities include a broad range of technical and managerial
problems in public works, finance, improvement of agriculture, and maintenance of
waterways.
In 1051 his father died and after a two year mourning period Shen Kua received his first
appointment as a local administrator at the age of twenty two. Soon after his appointment
he showed his skill in ability to plan by designing and overseeing a drainage and
embankment system that reclaimed some hundred thousand acres of swampland for
agriculture. A few years later he passed the national examinations and was assigned a
post in Yangchow. While in Yangchow he impressed the Governor Chang Ch'u so much that he
recommended that Shen be appointed to the department of Financial Administration. It was
about this time that he began to study astronomy.
His first works as an astronomer came when he set down clear explanations concerning the
sphericity of the sun and the moon as proved by lunar phases, of eclipse limits and the
retrogradation of the lunar nodes. These explanations gave the ability to visualize
motions in space Which in the past was only best implicit in numerical procedures of
traditional astronomy and seldomly discussed in technical writing. Because of this work
Shen was given an additional appointed as director of the Astronomical Bureau. His first
project as director was a major calendar reform. This reform started with a series of
daily observations of the stars that lasted over five years. While these observations
where being performed Shen realized the need for a major redesign of major astronomical
instruments. 
The most significant change that Shen made was to the gnomon. The gnomon was still being
used to measure the noon shadow and fix the solstices. Shen redesigned the armillary
sphere that is used to make angular measurements, and the clepsydra which determines the
time that observations are made. He improved the armillary sphere by improving the
diameter of the naked eye sighting tube. Shen noticed that the polestar could no longer
be seen in the sighting tube at night. He slowly widened the tube by using the plots of
the polestar three times a night for three months to adjust the aim. His new calibration
revealed that the tube was slightly three degrees off. The clepsydra also had calibration
problems as well, in the past day and night were separately divided by hours. Shen
realized that day and night hours were different from season to season. The time was read
from float rods in an overflow-tank. Shen saw these problems and proposed a new design
for these float tanks. 
Shen also made his mark in his discussions of solar, lunar, and eclipse phenomena. This
by far was the most extraordinary of his cosmological hypothesis that accounts for
variations in planetary motions that include retrogradation. Shen noted that the greatest
planetary anamoloy happened near stationary points. He proposed a model that suggested
that the planet moved in the shape of a willow leaf attached to one side of a periphery
circle. The way the planets changed thier direction of motion in respect to the stars was
explained by the travel from one point of the leaf to the other. This served the same
purpose as the epicycle served in Europe 
Shen's writings were in part considered to be the highest achievement in traditional
Chinese mathematical astronomy. After his impeachment from office at the age of fifty-one
Shen moved to a small piece of land in the country. It was there that Shen completed
three books and an atlas of China. One of these books was called Brush Talks From The
Dream Brook. This book includes some of Shen Kua's most elaborate ideas on such things as
regularities underlying the phenomenal, technical skills, deliberations of materia
medica, and many miscellaneous notes.