Janus and Epimetheus are captured swinging around Saturn's rings and past Dione in this movie sequence from Cassini.
The spacecraft repeatedly imaged the two moons just as they were about to round the outside edge of the rings, which were out of view to the left. Janus and Epimetheus orbit Saturn at nearly the same distance and velocity, although (as seen here) Janus is several tens of thousands of kilometers ahead of Epimetheus and farther from Cassini. Dione is actually quite far in the background compared to the small moons.
At the beginning of the movie, Epimetheus (113 kilometers, 70 miles across) is at left, Janus (179 kilometers, 111 miles across) is at center, and Dione (1,123 kilometers, 698 miles across) is at right.
The movie was created using 18 clear filter images taken over a period of about 30 minutes. The images were acquired by the Cassini spacecraft narrow angle camera on Dec. 30, 2005 from a mean distance of approximately 2.3 million kilometers (1.4 million miles) from Janus and 2.3 million kilometers (1.4 million miles) from Epimetheus. The image scale is approximately 14 kilometers (9 miles) per pixel on Janus and Epimetheus and 16 kilometers (10 miles) per pixel on Dione.
The Cassini-Huygens 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 Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.