Huygens Discovers Saturn's Moon Titan

Dutch astronomer Christiaan Huygens, observing Saturn through a 50-power refracting telescope he built with his brother Constantijn, identified a bright point of light near the planet. Over several nights of tracking, he confirmed it orbited Saturn, establishing it as a moon. He named it Luna Saturni. Titan became the sixth known planetary satellite after Earth's moon and Jupiter's four Galilean moons, extending telescopic astronomy beyond the Jovian system.