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 aid of mechanical instruments. Adriaan Metius Adriaan Adriaanszoon, called Metius, (9 December 1571 – 6 September 1635), was a Dutch geometer and astronomer born in Alkmaar. The name "Metius" comes from the Dutch word "meten" ("measuring"), and therefore means something like "measurer" or "surveyor." Adriaan Metius was born in Alkmaar, North Holland. His father, Adriaan Anthonisz, was a mathematician, land-surveyor, cartographer, and military engineer who from 1582 served also as burgomaster of Alkmaar. Metius' brother, Jacob Metius, worked as an instrument-maker and a specialist in grinding lenses. Also born in Alkmaar, Jacob died between 1624 and 1631. Little is