It is not certain who invented the telescope. Galileo Galilei and Johannes Kepler both made a name for themselves thanks to this versatile piece of equipment.
The development of the telescope is linked to two famous names: Galileo Galilei and Johannes Kepler. However, it is not certain who actually invented the telescope. Be that as it may, Galileo claimed that he had invented it while working out the laws of mechanics. He was able to convince the councillors of Venice of the usefulness of the telescope for military purposes and was rewarded with an appointment for life. Galileo passed on details of his instrument to Kepler for his expert opinion. At that time Kepler was mathematician and astronomer to the Court of Emperor Rudolf II in Prague; later he held the same position with the Upper Austrian Estates in Linz.
Kepler added some observations from the field of optics to Galileo’s calculations in mechanics. He had previously dealt with some problems in this field while making his calculations concerning the orbits of the planets. Some of his studies had also been devoted to defective vision and how it could be corrected by the use of spectacles.
The astronomical observations made using the telescope gave a boost to the supporters of the heliocentric conception of the universe, that is to say those who thought that the sun and not the earth was at its centre. In addition to such scientific and military uses the telescope could also be used for personal purposes. In the late eighteenth century,when spectacles were rather out of fashion as an aid to sight, miniature telescopes were used instead. They became a ‘must-have’ for the upper classes, who took them with them to the theatre, the hunt and on journeys.