Telescope earliest existing record of a telescope was a 1608 patent submitted to the government in the Netherlands by Middelburg spectacle maker Hans Lippershey for a refracting telescope. The actual inventor is unknown but word of it spread through Europe. [[Galileo Galilei|Galileo]] heard about it and, in 1609, built his own version, and made his telescopic observations of celestial objects. The idea that the [[Objective (optics)|objective]], or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using [[parabolic reflector|parabolic mirrors]]—reduction of [[spherical aberration]] and no
Adriaan Metius the university in 1603 and 1632. With his father and brother he established an instrument making business which specialised in optical instruments. The family business seems to have manufactured the precision Jacob's staffs used by Tycho Brahe for his star sightings. He died in Franeker. Though he scoffed at astrology, Metius is said to have spent a lot of time pursuing alchemy, especially the philosophers' stone. Metius published treatises on the astrolabe and on surveying. His works include "Arithmeticæ et geometriæ practica" (1611), "Institutiones Astronomicae Geographicae", and "Arithmeticæ libri duo: et geometriæ libri VI" (1640). Metius also manufactured astronomical instruments