Christian Huygens is in Astronomers.
On 14th April 1629 Christian Huygens was born.
On 25th March 1655 Christian Huygens (age 25) discovered Saturn's moon Titan; he named it Luna Saturni, literally Moon of Saturn, using a 2 inch telescope he and his brother had constructed in Feb 1656. It was the sixth moon discovered, the first being the Earth's moon, and the second to fifth, being the moons of Jupiter discovered by Galileo in Mar 1610.
On 8th July 1695 Christian Huygens (age 66) died.