What did Galileo use to observe stars ?

Galileo used a telescope to observe stars. A telescope is an optical instrument that magnifies distant objects, allowing for a closer and clearer view. Galileo's use of the telescope revolutionized astronomy as he discovered celestial bodies such as the moons of Jupiter and the phases of Venus, providing evidence to support the heliocentric model of the solar system. The invention and utilization of the telescope marked a significant milestone in the field of astronomy and our understanding of the universe.