关于这张图
This image is from Cassini's final observation of Saturn's icy moon Rhea (949 miles or 1,527 kilometers across) on May 2, 2017. The spacecraft was at the time high above the plane of Saturn's rings, looking down at Rhea's northern hemisphere. The northern rim of the giant Tirawa impact basin can be seen along the limb at left. (For a high-resolution view of Rhea, see PIA07763; Tirawa is the large basin at the one o'clock position in that view.) The image was taken in visible light with the Cassini spacecraft narrow-angle camera at a distance of approximately 230,000 miles (370,000 kilometers)…
