The question of who was the first to invent the telescope is as old as the instrument itself. The first certain source testifying to the invention of the telescope dates back to 1608. News of the invention spread rapidly throughout Europe, and already by April 1609 little telescopes about thirty centimetres long were to be found on sale, at the shops of spectacle-makers, in Paris and presumably in London. Galileo (1564-1642) fabricated his first telescope, with only three magnifications, in the summer of 1609. Soon he developed a telescope with twenty magnifications, that is, more powerful by far that all the others circulating through Europe at the time.
The application traces the history of Galileo's telescope and its subsequent developments. Some movies simulate the discoveries that Galileo made thanks to his telescope while downloadable documents allow you to discover how to make a Galileian Telescope.