Refracting telescope
Refractors were the earliest type of optical telescope. The first practical refracting telescopes appeared in the Netherlands about 1608, and were credited to three individuals, Hans Lippershey and Zacharias Janssen, spectacle-makers in Middelburg, and Jacob Metius of Alkmaar. Galileo Galilei, happening to be in Venice in about the month of May 1609, heard of the invention and constructed a version of his own. Galileo then communicated the details of his invention to the public, and presented the instrument itself to the Doge Leonardo Donato, sitting in full council.
History of the telescope
The ability of a curved mirror to form an image may have been known since the time of Euclid and had been extensively studied by Alhazen in the 11th century. Galileo, Giovanni Francesco Sagredo, and others, spurred on by their knowledge that curved mirrors had similar properties to lenses, discussed the idea of building a telescope using a mirror as the image forming objective. Niccolò Zucchi, an Italian Jesuit astronomer and physicist, wrote in his book "Optica philosophia" of 1652 that he tried replacing the lens of a refracting telescope with a bronze concave mirror in 1616. Zucchi tried looking into the mirror with a hand held concave lens but did not get a satisfactory image, possibly due to the poor quality of the mirror, the angle it was tilted at, or the fact that his head partially obstructed the image.