Terrestrial telescope, 1670-1700.
© Science Museum / Science & Society Picture Library
Of the many instruments invented in the 17th century, the telescope had the most impact. By the start of the 18th century, astronomers had observed the rugged surface of the Moon, the rings of Saturn, and the moons of Jupiter. This telescope dates from the late 17th century, and is stamped 'MR'. It would have been used for observation at sea or on land rather than for astronomical purposes.