What was the magnifying power of Galileo Galilei’s first telescopes?

Galileo Galilei’s first self-constructed telescope was a three-powered instrument, meaning it magnified objects three times.1

Following this initial invention in 1609, Galileo quickly refined his techniques for lens grinding to produce increasingly powerful instruments. By August 1609, he presented an eight-powered telescope to the Venetian Senate, and by the fall of that same year, he was observing the heavens with instruments that magnified up to 20 times.1