Whose telescope discovered the moons of Jupiter?

In January 1610, the Italian scientist Galileo Galilei turned his improved telescope toward the planet Jupiter and observed what he first thought were small fixed stars nearby. Over several nights he realised these points of light were moving around Jupiter, and he concluded they were moons orbiting the planet. These four largest moons, Io, Europa, Ganymede, and Callisto, are now called the Galilean moons in his honour. The discovery was revolutionary because it showed clearly that celestial bodies could orbit something other than the Earth, directly challenging the long-held geocentric belief that everything revolved around our planet. It provided strong support for the Sun-centred model of Copernicus. Galileo telescopic discoveries, published in a book called the Starry Messenger, transformed astronomy but also brought him into conflict with the Church.