Telescope

The first telescope was most probably constructed by a Dutch optician H. Jansen in 1604. He might have used the existing Italian construction. Galileo Galilei improved the construction in 1609 by increasing the magnification to 30 times.

A telescope consists of a simple lens ( a convergent lens) and an eyepiece which is a divergent lens, both placed in a tube at a meticulously matched distance. When Galileo looked into the sky through this apparatus, he saw the sky magnified by hundreds and thousands of times more than what has been observed by the scientists of all past epochs.

Thanks to this discovery we can observe distant stars at the edges of the Universe.