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.
Reber Radio Telescope
The telescope was built by astronomer Grote Reber in his back yard in Wheaton, Illinois in 1937, following up on the research of Karl Jansky, the discoverer (in 1931) of radio waves emanating from the Milky Way. It was the second radio telescope ever built (after Jansky's dipole array), and the first parabolic radio telescope, serving as a prototype for the first large dish radio telescopes such as the Green Bank Telescope and Lovell Telescope constructed after World War 2. Reber was the world's only radio astronomer at the time, and his construction of the telescope and the sky surveys he did with it helped found the field of radio astronomy, revealing radio sources such as Cassiopeia A and Cygnus X-1 for the first time.