NASA / JPL / SSI / color composite by Emily Lakdawalla
Calypso, only 34 x 22 x 22 kilometers in diameter, occupies the L4 Lagrangian point in Tethys' orbit -- it sits in a point 60 degrees ahead of Tethys.
Cassini passed within 22,000 kilometers of the moon on February 13, 2010, for the best look yet at its smooth, icy surface. This view is a color composite from Cassini's raw images, red, green, and blue frames overlaid on a stacked composite of red, green, blue, and clear images. (Stacking mostly serves to decrease the artifacts caused by the JPEG format of the raw images.)