Rotational work is common for the field operator, often involving eight days of 10-hour shifts followed by six days off. Unlike plant operators, field operators usually work days. Evening call-outs can occur if maintenance or production issues arise at a well site the operator covers.
Before the advent of telescopic photography, eight moons of Saturn were discovered by direct observation using optical telescopes. Saturn's largest moon, Titan, was discovered in 1655 by Christiaan Huygens using a 57-millimeter (2.2 in) objective lens on a refracting telescope of his own design. Tethys, Dione, Rhea and Iapetus (the  Sidera Lodoicea ) were discovered between 1671 and 1684 by Giovanni Domenico Cassini.
Their journeys around the ringed planet average from half an Earth day to just over four Earth years. Saturn's moons formed early in the history of the solar system. One of the moons, Titan, makes up 96 percent of the mass orbiting the planet. Scientists think that the system may have originally housed two such moons, but the second broke up, creating the debris that formed the rings and smaller, inner moons.