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
Metius (crater) but generally it has a smoothed down appearance that is almost free of terraces. The floor is relatively flat with low central peaks. The most prominent crater on the floor is Metius B, located near the northeast rim. The eponym for this crater is the Dutch geometer and astronomer Adriaan Adriaanszoon, who went by the name of Metius. By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Metius. Metius (crater) Metius is a lunar impact crater located in the rugged highlands to the southeast of