The dark region seen in the image is called Cassini Regio, in honor of Giovanni Domenico Cassini
, the Italian astronomer who discovered Iapetus in October 1671 and whose name also lends itself to the spacecraft that captured this image.
1712 Giovanni Domenico Cassini
died, aged 87; an Italian-born French astronomer; appointed the first French Astronomer Royal; discovered four satellites of Saturn and correctly explained the unusual variability of Iapetus; noticed a division in Saturn's rings, now known as Cassini's division.
Saturn's moon Iapetus has long been known as two-faced, ever since Giovanni Domenico Cassini
found in 1671 that it's much brighter when on the western side of its orbit than on the eastern side.
Astronomer-craftsmen like Giambattista Riccioli, Giovanni Domenico Cassini
, and their colleagues revamped older meridiane or built splendid new ones to exacting specifications in San Petronio (Bologna) and Saint Sulpice (Paris), and Santa Maria degli Angeli (Rome), among several others.
Observations made there by astronomer Giovanni Domenico Cassini
, and confirmed by independent observers, notes Heilbron, "amassed unimpeachable evidence" in favor of the Copernican theory that had been condemned by Pope Urban VII and the Inquisition only a quarter-century before.
After years spent in a frustrating search, renowned astronomer Giovanni Domenico Cassini
must have wondered if he would die before seeing a legendary sunspot grace the heavens again.
Two other of Saturn's seven moons, Titan and Enceladus, also have oceans deep within them but the new data confirms the same to be true for Dione-discovered in 1684, along with three other of Saturn's moons, by Giovanni Domenico Cassini
Cassini was born with the Italian name Giovanni Domenico Cassini
in the picturesque hilltop village of Perinaldo, 50 kilometers (30 miles) from Nice, then part of the Duchy of Savoy.
Ever since Giovanni Domenico Cassini
discovered it in 1671, telescope users have marveled over Saturn's large outer satellite Iapetus.
Nor is the spot likely to disappear; it was observed by Giovanni Domenico Cassini
as long ago as 1665, and one theoretical estimate gives a lifetime of 100,000 years.
In this location, the great 17th-century French astronomer Giovanni Domenico Cassini
thought he saw a bright cloud that soon dissipated, leaving behind a newly formed crater.