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.
The moon was discovered by Dutch astronomer Christiaan Huygens in 1655. The Huygens lander probe sent to the moon aboard NASA's Cassini spacecraft by the European Space Agency is named in his honor. Huygens was the first human-built object to land on Titan's surface. [Amazing Photos of Titan] Titan's diameter is 50 percent larger than that of Earth's moon. Titan is larger than the planet Mercury but is half the mass of the planet. Titan's mass is composed mainly of water in the form of ice and rocky material. Titan has no magnetic field.