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
Theodore Janssen Theodore Janssen Sir Theodore Janssen of Wimbledon, 1st Baronet (c. 1658 – Wimbledon, London, 22 September 1748) was a French-born English financier and Member of Parliament who after a long and successful career in commerce was ruined and disgraced by his part in the South Sea Bubble. Janssen was born in Angoulême, France, son of the paper maker Abraham Janssen and Henriette Manigault. His grandfather, Theodore Janssen de Heez, had taken refuge in France from the Duke of Alba's persecution in the Netherlands. Janssen moved to England in 1680, making his home at Wimbledon, where he bought Wimbledon manor. He