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.
Cornelis Drebbel
One of the optical devices some historians believe Drebbel invented when he was working for the Duke of Buckingham was the compound microscope. The device appeared in Europe around 1620 with the earliest account being Dutch Ambassador Willem Boreel's 1619 visit to London where he saw a compound microscope in Drebbel's possession, described as an instrument about eighteen inches long, two inches in diameter, and supported on 3 brass dolphins. In 1621 Drebbel had a compound microscope with two convex lenses. Several of his contemporaries, including Christiaan Huygens, credited the invention of the compound microscope to Drebbel. The invention has many counter claims including Dutch spectacle-maker Johannes Zachariassen's claim that Drebbel stole the idea from him and his father, Zacharias Jansen, and claims that Galileo Galilei used his telescope after 1610 as a type of compound microscope. In 1624 Galileo saw Drebbel's design for a microscope in Rome and created an improved version of it to send to Federico Cesi, founder of the Accademia dei Lincei, who used it to illustrate "Apiarum", his book about bees.