After building his first telescopes, Galileo demonstrated the new instrument ... That discovery helped support a heliocentric model of the solar system — a belief so radical at the time that ...

His observations of the night sky in the early 1600s confirmed a new model of ... the solar system, Galileo was working on practical problems. And his early goals for the telescope weren't so ...

When Italian astronomer Galileo Galilei heard rumors of the first practical telescope at the beginning of the 17th century, he was quick to craft his own version and turn it toward the heavens.