1625: On 8 June 1625, the French-Italian scientist Giovanni Cassini was born.
He was the most notable space observer since Galileo. Heading the Paris Observatory for many years, Cassini was the first to observe seasonal changes on Mars and measure its parallax (distance from Earth), setting the scale of the Solar System for the first time. He was the first to describe the bands and spots on Jupiter, and studied the orbits of Jupiter's moons.
He discovered four moons around Saturn, but is best remembered for first seeing the division (now named after him) between the ‘A’ and ‘B’ rings around Saturn.