This animation of GOES-12 visible channel images shows the eye of Hurricane Dean on 20 August 2007. The image interval during this animation is once every 15 minutes. Note that the low cloud features within the eye region appear to be rotating anticyclonically (clockwise) -- this is an "optical illusion, similar to the "stobe effect". The low cloud features were moving so quickly that their true motion could only be ascertained by viewing images more frequently than once ever 15 minutes.