Saturn rotates!

This image is a composite of images exposed through red, green and blue filters. In a northern cloud band you can see a bright spot which is reddish on the left, green in the middle and blue on the right. The time between the red and green images was 8 minutes and between the green and blue images was 10 minutes thus the movement of spot demonstrates rotation of the planet.

A full rotation of Saturn required about 10 hours and 39 minutes as measured by the clouds and about 10 hours and 47 minutes as measured by core rotation (see Nature vol 441, p 62).

First image made on 1 June 2011 at 13:51:14 UT.