 In 1609 , Galileo was , along with Englishman Thomas Harriot and others , among the first to use a refracting telescope as an instrument to observe stars , planets or moons . The name " telescope " was coined for Galileo 's instrument by a Greek mathematician , Giovanni <unk> , at a banquet held in 1611 by Prince Federico Cesi to make Galileo a member of his Accademia dei Lincei . The name was derived from the Greek tele 
