CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Moons by the Bunch

Moons by the Bunch
PIA 11480

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  Three moons have bunched themselves together in this image of Saturn's rings.

Janus (179 kilometers, 111 miles across) sits bright and overexposed outside the faint F ring. Prometheus (86 kilometers, 53 miles across) lies inside the F ring to the left of the center of the image. Tiny Daphnis (8 kilometers, 5 miles across) is present but not visible in the thin Keeler Gap of the A ring just below Prometheus in this image.

This view looks toward the sunlit side of the rings from about 20 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on March 2, 2009. The view was acquired at a distance of approximately 1.1 million kilometers (684,000 miles) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 47 degrees. Image scale is 63 kilometers (39 miles) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. 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 was designed, developed and assembled at JPL. 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.

For more information about the Cassini Equinox Mission visit, and

Credit: NASA/JPL/Space Science Institute
Released: April 28, 2009 (PIA 11480)
Image/Caption Information

Alliance Member Comments
mipsandbips (Apr 28, 2009 at 9:17 PM):
This is a great opportunity to see Janus in orbit parallel to Prometheus.
One can really appreciate the visual confirmation of the size of Janus at
111 miles across, amazingly close to double the size compared to Prometheus' diameter of 53 miles!