The first spectacles, designed to correct farsightedness ... "objective" lens—the convex lens at the far end of the telescope—Galileo ground a lens larger than he needed, for example.

Maybe you received a telescope during the holiday season, or perhaps you’ve gifted yourself with a scope. I want you to get ...

Second, you soon want a bigger telescope. Galileo, who first trained a telescope on the night sky 400 years ago this fall, pioneered this two-step program. First, he marveled at what he could see.

Italian astronomer Galileo Galilei peered through his newly improved 20-power homemade telescope at the planet Jupiter. He ...

Still, even Galileo recognized the ground-based uses of telescopes. After building his first telescopes, Galileo demonstrated the new instrument to the Venetian Senate, including military leaders.

Nearly 415 years ago to the day astronomer Galileo Galilei discovered the moons surrounding Jupiter looking through his homemade telescope.

Galileo Galilei, with a homemade telescope, noticed three points of light near Jupiter. Initially believing they were distant stars, Galileo’s repeated observations over several nights and realized ...

Humans like to think by analogy, and this method often works well for advancing knowledge. For instance, when Galileo first turned his new telescope towards the heavens in 1609–10, he quickly noted ...

📅 Today in History: In 1610, Italian astronomer Galileo Galilei, through improvements he made on a homemade telescope, first observed Jupiter’s four Galilean moons: Ganymede, Callisto, Io and Europa.