He used it to study the moon, Jupiter's moons, Saturn, Venus and the sunspots on the sun.
telescope
after he made it
A telescope.
By 1609 Galileo had a telescope that magnified 20x
Galileo
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Galileo
Galileo !
Galileo
Galileo was the first person to use a telescope for astronomical research.
Galileo saw in his telescope when it was 1995
He invented the reflecting telescope. Galileo was the first to use the telescope for studies of the heavens.