History of the telescope
The earliest known telescope appeared in 1608 in the Netherlands when an eyeglass maker named Hans Lippershey tried to obtain a patent on one. Although Lippershey did not receive his patent, news of the new invention soon spread across Europe. The design of these early refracting telescopes consisted of a convex objective lens and a concave eyepiece. Galileo improved on this design the following year and applied it to astronomy. In 1611, Johannes Kepler described how a far more useful telescope could be made with a convex objective lens and a convex eyepiece lens and by 1655 astronomers such as Christiaan Huygens were building powerful but unwieldy Keplerian telescopes with compound eyepieces.
Leonard Digges (scientist)
The writings left by Digges' colleague William Bourne contain further detail on the experiments with lenses and mirrors conducted by Leonard Digges and his son. It is these details which led some researchers, most notably Colin Ronan, to claim that Leonard Digges invented a functioning telescope sometime between 1540 and 1559. The description seemed to suggest that Digges created a rudimentary instrument incorporating lenses and a concave mirror, in a manner rather different from a modern reflecting telescope. However, the construction of lenses to the required optical precision would have been very difficult in the 16th century, and the construction of an adequate mirror would have been much harder still. It is doubtful that Digges built a successful instrument, and the optical performance required to see the details of coins lying about in fields, or private activities seven miles away was far beyond the technology of the time.