Based on Observations of the Position of Stars

Man has always been fascinated by the apparent movement of the stars in the night sky. Based on observations of the position of stars, man learnt to predict a number of natural phenomena like the seasons, eclipses, floods and so on. Here are some of the great men in this field.

1) Aristarchus (3rd century BC) A Greek astronomer who was 2000 years ahead of his time in believing that earth moved around the sun. The Greeks believed that the earth was spherical in shape but were sure that the earth was the centre of the universe.

2) Claudius Ptolemaeus or Ptolemy (2nd century AD) was a famous astronomer, geographer and mathematician from Egypt. He thought that the earth was the centre of the universe, with the sun, the moon and the stars revolving around it. His ideas held good for nearly 1400 years. His list of 1022 stars very voluble to later astronomers. His maps of Asia and Africa and his notes on latitudes and longitudes led Columbus to believe that he could reach India by sailing west.

3) Nicolas Copernicus (1473-1543) did not believe in Ptolemy's theory about the Earth being the centre of the universe. His theory was against the belief of the Roman Catholic Church. He was therefore expelled from the Church. He published a book which came out just before he died, in which is theory was explained in detail.

4) Galileo Galilei (1564-1642) was an Italian mathematician, physicist and astronomer. He learnt of the invention of the simple telescope and designed one self. He was the first to examine the heavens with a telescope. His research supported Copernicus' view that the solar system was heliocentric and not geocentric i.e., the planets, including the Earth, revolved round the sun. Galileo also invented the pendulum which was later used in clocks.

5) Johannes Kepler (1571-1630) was one of the founders of modern astronomy. With the help of the Copernican theory, he developed his laws about the movement of the planets around the sun. Newton used Kepler's laws to put forth his own theories on the motion of bodies and gravitation.

6) Tycho Brahe (1546-1601) was a Danish astronomer who made many accurate astronomical instruments. Two observatories were built for him by the king. He supported the Copernican theory about the solar system.

7) William Herschel (1738 -1822) was an expert at grinding lenses and mirrors and he built the largest telescope of his time. He discovered the planet Uranus, binary stars and two satellites of Saturn.

Indians were not lagging behind when it came to watching the night sky.

8) Lagadha (c900BC), who lived in Kashmir, systematized astronomy in a text Vedanga Jyotisa. He could probably be called the world's first astronomer.

9) Aryabhatta (476-520) was the first astronomer in the world to arrive at the currently accepted theory that the earth is round; it rotates on its axis, and revolves round the sun.

10) Gargya, a sage belonging to the Vedic period, listed out 27 Indian constellations or nakshatras. These nakshatras are groups of stars which mark the path of the moon in the sky.

11) Sawai Jai Singh II (1686-1743) built first observatories called Jantar Mantar.

12) The Birla Planetarium at Calcutta was set up in 1962. The oldest planetarium in the world is the Jena Planetarium in Germany, set up in 1923. Telescopes are used to observe the distant stars. The most famous are the ones at Mt. Palomar in California, USA, and the Jodrell bank radio telescope in England. In India we have a radio telescope at Udhagamandalam and an optical telescope at Kavalur, both in Tamil Nadu. A new one called GMRT is coming up near Pune. The humble space Telescope is a powerful optical telescope which was launched into the earth's orbit in 1990. Did you know?

Science City at Calcutta, inaugurated in 1997, has a space theatre which, with its titled dome, can take one through the world of distant stars and planets. The Astrovision projection makes you feel you are actually there, on the spot, among the stars. The Space Time Rocket makes it possible for you to travel through an erupting volcano, in a simulated space flight. How would you like that -to be in a volcanic eruption or up among the twinkling stars!