Hans Lippershey also known as Johann Lippershey or Lipperhey invented the telescope.
Hans Lippershey (ca. 1570-1619), a German-Dutch lens grinder and spectacle (glasses) maker, is generally credited with inventing the telescope. This is because in 1608 Lippsershey became the first scientist to apply for a patent for the telescope. (A patent is a grant made by a government that allows the creator of invention the sole right to make, use, and sell that invention for a set period of time.) Two other inventors, Zacharias Janssen and Jacob Metius, also developed telescopes around this time. Modern historians consider both Lippershey and Janssen to be likely candidates for the title of "inventor of the telescope," with Lippershey possessing the strongest claim.
In 1609, Italian astronomer Galileo (1564-1642) developed his own refractor telescope for astronomical studies. A refractor telescope is the simplest type of telescope; light enters through one end of a tube and passes through a glass lens, which bends the light rays and brings them into focus. The light then strikes an eyepiece, which acts as a magnifying glass. Although small by today's standards, the telescope enabled Galileo to observe the Milky Way and to identify craters on the moon's surface.
Sources: The Great Scientists, vol. 7, p. 162; Travers, Bridget, ed. World of Invention, pp. 618-19.