This important measurement was made using Cassini's INMS instrument, which detects gases with the goal of determining their composition. INMS was designed to sample the upper atmosphere of Saturn's large, smoggy moon Titan. However, after Cassini's surprising discovery of a tall plume if icy spray erupting from cracks on Enceladus in 2005, planetary scientists turned its detectors to that small moon.
Titan orbits Saturn once every 15 days and 22 hours. Like Earth's large Moon, in addition to many other moons in our Solar System, Titan's rotational period is precisely the same as its orbital period. This means that Titan only shows one face to its parent-planet, while the other face is always turned away.
Were you aware of the fact that the moon has a huge impact on fishing? I used to find this hard to believe, but it's true. And you don't have to be a rocket scientist to understand how the moon and fishing fit together. As a matter of fact, by spending about a half an hour educating yourself can pay huge dividends in not only the amount of fish that you catch, but also the size of those fish. All because of the moon, who would have thought?