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.
Newton's reflector
There has been much confusion and dispute concerning the telescopes that Newton built, but it is now clear that his first telescope was a prototype that he constructed in 1668. This was seen only by a few friends at Cambridge and very little is known of it. This prototype had a mirror a little over an inch in diameter, probably 1.3 inches, and around 6 inches in length. Newton seldom referred to this prototype in later years and so his second scope is often called his first.