Lynn Berger, age 11, of Pittsfield, Mass., for her question:
WHO INVENTED THE TELESCOPE?
The telescope is a lens, mirror or other reflecting surface used to form an image of a distant object, together with a microscope to enable the observer to examine the image in detail, or a photographic, camera or some form of spectroscopic apparatus. The telescope was invented in Holland, but some controversy exists over the actual inventor.
Credit for the telescope's invention usually goes to Hans Lippershey, a Dutch spectacle maker. He came up with the idea in 1608, but was refused a patent for his instrument.
After hearing of Lippershey's invention, an Italian astronomer named Galileo built his first telescope in 1609. It was a crude instrument. In fact, the most powerful instrument that Galileo built magnified objects only 33 times.
Nevertheless, Galileo made some outstanding discoveries. He was able to see the rings of Saturn, four of the satellites of Jupiter and the mountains and craters on the moon.
A German astronomer named Johannes Kepler discovered the principle of the astronomical telescope with two convex lenses. This idea was actually employed in a telescope constructed in 1630 by a German Jesuit astronomer named Christoph Schenier.
The invention of the achromatic object glass in 1757 by John Dollond, a British optician, and the improvement of optical flint glass, which started in 1754, soon permitted the construction of improved refracting telescopes. These telescopes all had modest dimensions and until well into the 19th Century, few were larger than 12 inches in diameter.
Methods of making large disks of flint glass were discovered in the late 18th Century by Pierre Guinand, a Swiss optician who became associated with Joseph von Fraunhofer, a German optician and physicist. Guinand's discovery permitted the manufacture of telescopes as large as 40 inches in diameter.
One of the first reflecting telescopes was built by Sir Isaac Newton in England in 1668.
In 1931 a Russian born optician named Bernard Schmidt invented a combination reflecting refracting telescope that could accurately photograph large areas of the sky. The Schmidt telescope contains a thin lens at one end and a concave mirror with a correcting plate at the other end. The largest Schmidt telescope, with a 48 inch lens and a 72 inch mirror, is at Palomar Observatory on Mount Palomar in California.
An important innovation in telescope design is the multiple mirror telescope (MMT), the first of which was completed in 1979 on Mount Hopkins, near Amado, Ariz. The MMT employs an array of six 72 inch concave mirrors operating in unison to achieve the light gathering effectiveness of a single 76 inch reflector.
The largest fully operable reflecting telescope is the 236 inch instrument near Zelenchukskaya in Russia, in operation since 1976. Next is the 200 inch at Palomar, in use since 1948.