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.
Lovell Telescope
Between 1972 and 1973, the telescope was used for "a detailed survey of the radio sources in a limited area of the sky … up to the sensitivity limit of the instrument". Among the objects catalogued was the first gravitational lens, which was confirmed optically in 1979 after its position was found to coincide with a pair of faint blue stars by using the Mark I as an interferometer with the Mark II. The telescope was also involved in the detection of the first Einstein ring in 1998, in conjunction with observations made with the Hubble Space Telescope.