Optical telescope
The telescope is more a discovery of optical craftsmen than an invention of a scientist. The lens and the properties of refracting and reflecting light had been known since antiquity and theory on how they worked were developed by ancient Greek philosophers, preserved and expanded on in the medieval Islamic world, and had reached a significantly advanced state by the time of the telescope's invention in early modern Europe. But the most significant step cited in the invention of the telescope was the development of lens manufacture for spectacles, first in Venice and Florence in the thirteenth century, and later in the spectacle making centers in both the Netherlands and Germany. It is in the Netherlands in 1608 where the first recorded optical telescopes (refracting telescopes) appeared. The invention is credited to the spectacle makers Hans Lippershey and Zacharias Janssen in Middelburg, and the instrument-maker and optician Jacob Metius of Alkmaar.
Linden Observatory Complex
Up until the 17th century, astronomy was positional and depended on observations of the naked eye. In the early 17th century a new instrument, the telescope was invented by Hans Lipperhey and quickly taken up and improved upon by Galileo Galilei. In 1610, armed with his 20 XX refractor telescope, Galileo discovered four moons of Jupiter and for the first time in the history of the world observed the movement of a satellite around a planet. Using his telescope Galileo also observed that the phases of Venus were similar to lunar phases and argued that these observations empirically supported the theory that the earth moves around the sun.