Page 256 - Inventions - A Visual Encyclopedia (DK - Smithsonian)

Telescopes

Galileo’s
original
telescope
Telescopes have come a long way in the four centuries
since the lensmaker Hans Lippershey assembled two

lenses at either end of a long tube around 1608. Today,
they have become huge machines capable of detecting

galaxies at the edge of the universe and invisible
radiation from gas and dust between the stars.
SPACE

Early telescope William Giant reflectors
Herschel’s
■ ■ What? Galileo’s telescope 40-ft (12-m) ■ ■ What? The first giant telescope
■ ■ Who? Galileo Galilei telescope ■ ■ Who? William Herschel
■ ■ Where and when? Italy, 1609 ■ ■ Where and when? UK, 1789
Several astronomers built their own The German-born astronomer William
telescopes after hearing of Lippershey’s Herschel built the best reflecting telescopes
invention, but the most successful was the of the time after settling in the UK. After
Italian Galileo Galilei (see pp.258–259). his 1781 discovery of Uranus, he was
Through careful study, he increased the financed by King George III and
power of his telescopes from three times built an enormous telescope with
magnification (3x) to 20 times (20x), which a 4-ft (1.2-m) mirror, mounted on a
allowed him to make important discoveries huge turntable that allowed it to point
about the universe. in different directions.

Mirrors for magnification Radio telescope

■ ■ What? Newton’s reflector ■ ■ What? The Lovell Telescope and focus them. In the 1950s, the British
■ ■ Who? Isaac Newton ■ ■ Who? Bernard Lovell and Charles Husband astronomer Bernard Lovell built the first
■ ■ Where and when? UK, 1668 ■ ■ Where and when? UK, 1957 large “dish” telescope at Jodrell Bank
near Manchester.
While studying the properties of light The science of radio astronomy began in
in the 1660s, the English scientist Isaac the 1930s when astronomers discovered
Newton realized that a curved mirror radio waves coming from celestial objects
could bend light to a focus just as well other than the sun. Because radio waves
as a lens. His “Newtonian” telescope are longer than visible light waves, they
avoided the need much larger telescopes to capture
distortions that
plagued early Reflecting metal dish 250 ft (76.2 m)
across gathers radio waves
lens-based designs.

Antenna is focal point for
radio waves, which then
Eyepiece generate electrical signals

Lovell Telescope
Replica of near Macclesfield,
Newton’s telescope Cheshire, UK
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