Early Telescopes
It was well
known after the 14th century
that lenses could correct vision. Convex lenses corrected
farsightedness and
concave lenses corrected nearsightedness. Through a
combination of these lenses
the first known telescopes were invented in the 17th
century. The
image below is the earliest drawing of a telescope. It was
able to magnify
objects 3 to 4 times.
The
original telescope could not be patented due to
its easily copied design. Once the idea of the invention
was disseminated many
interested parties began to improve on the design. The
most famous of these was
Galileo Galilei. Galileo was an Italian physicist and
astronomer. He built
several telescopes including one that could magnify twenty
times.
He used
this telescope to observe mountains and
craters on the moon, the moons of Jupiter, and the rings
of Saturn. Galileo
took note of the orbits of other planets and deduced that
they must be orbiting
the sun and not the earth which was the popular theory at
that time. He was
almost burned at the stake for this controversial idea.
Today the heliocentric
theory which was first put forth by Copernicus and later
popularized by Galileo
is the accepted explanation of the planetary orbits.