Giovanni Domenico Cassini in the context of "Cassini oval"

Viscount Alexandre Henri Gabriel (vicomte) de Cassini (9 May 1781 – 23 April 1832) was a French botanist and naturalist, who specialised in the sunflower family (Asteraceae) (then known as family Compositae).

He was the youngest of five children of Jean-Dominique, Comte de Cassini (Cassini IV), famous for completing the map of France, who had succeeded his father as the director of the Paris Observatory. He was also the great-great-grandson of famous Italian-French astronomer, Giovanni Domenico Cassini, discoverer of Jupiter's Great Red Spot and the Cassini division in Saturn's rings.

Dione (/daɪˈoʊni/) is the fourth-largest moon of Saturn. With a mean diameter of 1,123 km and a density of about 1.48 g/cm, Dione is composed of an icy mantle and crust overlying a silicate rocky core, with rock and water ice roughly equal in mass. Its trailing hemisphere is marked by large cliffs and scarps called chasmata; the trailing hemisphere is also significantly darker compared to the leading hemisphere.

The moon was discovered by Italian astronomer Giovanni Domenico Cassini in 1684 and is named after the Titaness Dione in Greek mythology. Dione was first imaged up-close by the Voyager 1 space probe in 1980. Later, the Cassini spacecraft made multiple flybys of Dione throughout the 2000s and 2010s as part of its campaign to explore the Saturn system.

Tethys (/ˈtiːθɪs, ˈtɛθɪs/) is the fifth-largest moon of Saturn, measuring about 1,060 km (660 mi) across. It was discovered by Giovanni Domenico Cassini in 1684, and is named after the titan Tethys of Greek mythology.

Tethys has a low density of 0.98 g/cm, the lowest of all the major moons in the Solar System, indicating that it is made of water ice with just a small fraction of rock. This was confirmed by the spectroscopy of its surface, which identified water ice as the dominant surface material. A further, smaller amount of an unidentified dark material is present as well. The surface of Tethys is very bright, the second-brightest of the moons of Saturn after Enceladus, and neutral in color.

Iapetus (/aɪˈæpətəs/) is the outermost of Saturn's large moons. With an estimated diameter of 1,469 km (913 mi), it is the third-largest moon of Saturn and the eleventh-largest in the Solar System. Named after the Titan Iapetus from Greek mythology, the moon was discovered in 1671 by Giovanni Domenico Cassini.

A relatively low-density body composed mostly of ice, Iapetus is home to several distinctive and unusual features, such as a striking difference in coloration between its dark leading hemisphere and its bright trailing hemisphere, as well as a massive equatorial ridge that runs three-quarters of the way around the moon.