In 1609, an Italian mathematician named Galileo Galilee peered through an odd new device he had invented to look at the stars in the night sky. Suddenly, this well known and familiar place revealed itself as a barely exposed mystery. It was then that Galileo knew this was a ground
breaking device.

The moon is a gray-white orb to the naked eye. Looking through this new instrument, Galileo
was able to see shadows and bright spots on the surface of the moon. He could see that the
moon also had mountains and valleys.

At the time, the planets were thought to be odd stars that wandered the sky. Through
Galileos device, he could see that the planets were accompanied by moving pinpoints of lights which were moons of their own!

Galileo quickly published his discoveries in a bulletin he titled Message from the Stars. His claims, at first, were met with wonder and excitement. He presented his new device to the leaders of the time including the Catholic Church in Rome.

Eventually this device would be named telescopio. In Greek, telescopio means to see at a
distance. This would eventually evolve into the word telescope, but it certainly was an apt name for this new invention.

Galileos telescope was a simple instrument compared with the ones we use today. It was a
tube with two lenses: the convex primary lens that curved outward and the concave eyepiece
lens that curved inward. He built the device after hearing about the newly invented spyglass which was an instrument used by the military to peer into enemy camps.

This first telescope used the same principle that all telescopes would eventually rely on. That principle held that the combination of the two lenses gathered more light than the human eye could collect on its own.

The lenses would focus that light and form an image. Because theimage was formed by the bending of light, or refraction, these telescopes came to be known asrefracting telescopes, or simply, refractors.