NASA Explains Starless Saturn’s Image

Credit: NASA
Credit: NASA

Why do we not see any stars in this beautiful picture of Saturn’s rings and two of Saturn’s moons (Bione, left and Epimetheus, right) shot by the Cassini spacecraft?

As anyone here on Earth who has tried to shoot the stars in the night sky knows, to record the faint lights of stars requires a very long exposure of many seconds, even minutes. But Saturn’s main rings, along with its moons, are much brighter than most stars and so do not require a long exposure. In fact, the picture was snapped using a very short exposure of 10 milliseconds (1/100 sec.), too short to record the stars in the black sky.

This image was taken in visible light with the Cassini spacecraft wide-angle camera on April 2, 2016. The view was obtained at a distance of approximately 257,000 miles (413,000 kilometers) from Saturn. Image scale is 15 miles (25 kilometers) per pixel.