The Crater Gradient
The Cassini spacecraft investigates the craters and deep valleys on Dione during a close approach in April 2007.
Significant variations in the density of impact craters on the surface of Dione can be seen here, with more craters seen on the right side of this mosaic (on Dione's sub-Saturn hemisphere) than on the left (on Dione's anti-Saturn hemisphere). The southern end of the bright Palatine Linea fracture system can be seen near the bottom of the mosaic. Along the terminator, at lower left, part of a large impact basin can be seen.
The mosaic is an orthographic projection centered at 33 degrees South, 74 degrees West, over the southern part of Dione's leading hemisphere. An orthographic view is most like the view seen by a distant observer looking through a telescope. North on Dione (1,126 kilometers, or 700 miles across) is up and rotated 6 degrees to the right.
The monochrome view uses a combination of images taken with spectral filters sensitive to wavelengths of light centered at 338, 568 and 930 nanometers.
The images in this mosaic were taken with the Cassini spacecraft narrow-angle camera on April 24, 2007 at a distance of approximately 121,000 kilometers (75,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 55 degrees. Image scale is 723 meters (2,371 feet) per pixel.