February 16, 2015
In reality, Janus and the rings both orbit Saturn and are only weakly connected to each other through their mutual gravitational tugs. At specific locations in the rings, these gravitational tugs result in orbital resonances, which lead to some beautiful waves being created in the rings. See Structure in the Spiral for an example. Janus is 111 miles, or 179 kilometers, across.
This view looks toward the sunlit side of the rings from about 19 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 5, 2014.
The view was acquired at a distance of approximately 1.2 million miles (2.0 million kilometers) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 35 degrees. Image scale is 7 miles (12 kilometers) per pixel.
The Cassini mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
Credit: NASA/JPL-Caltech/Space Science Institute