In Pursuit of Starlight:
The easiest method of studying light from a cosmic object is to collect it through a telescope and record it on a photographic plate. photographic plate are exposed for long periods of time-sometimes night after night-to the light being collected by a telescope aimed at distant stars. Since the Earth rotates on its axis, the stars appear to move in the sky. The telescope is rotated following the daily movement of the stars at which it is aimed. Thus, its movement is synchronised with the movement of the stars being studied, stars, far too faint for human eyes, slowly begin to register on the plate. This method of collecting and investigating light from the cosmos is called optical astronomy. Over the centuries, astronomers have refined the telescope from the first crude lenses of Galilee's day to giant 'telescopes in use today. Three simple pieces of glass, the lens, the mirror and the prism over the period of a few hundred years. have turned into sophisticated and powerful tools in human hands. Shouldn't we marvel at the ingenuity of the human mind'? As of today, a huge optical telescope called the Hubble space telescope. after Edwin IIubble, is in orbit around the earth. Several large telescopes are stationed in the USA, Hawaii, Australia, Chile, Russia, U.K. etc.