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Two moons, Rhea and Dione, join the planet and its rings in this view from Cassini. Rhea and Dione are respectively the second and fourth largest moons of Saturn, but they seem tiny compared to the planet. Dione (1123 kilometers, 698 miles across) is near the center of the image. Rhea (1528 kilometers, 949 miles across) is on the right. The shadow cast by a third moon, Tethys, is also visible near the bottom of the image, south of the shadows cast by the planet's rings and near the terminator between light and dark. Tethys is not shown here. Part of the large storm that has been churning through the northern atmosphere for months can be seen in the top left of the image. This view looks toward the northern, sunlit side of the rings from just above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on March 11, 2011 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers. The view was obtained at a distance of approximately 2.9 million kilometers (1.8 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 94 degrees. Image scale is 172 kilometers (107 miles) per pixel on Saturn. [Caption updated Jan. 5, 2012.] |