Animation  of Dual Transit 
This sequence of images show a dual shadow transit.  When the animation starts the two moons Europa and Io are to the left of the planet and the Great Red Spot (GRS) is near the center.  As the animation progresses you can see the GRS move towards the right edge of the planet, the shadow of the moon Io appears and then the shadow of the moon Europa.  There are a few frames where you can see Io itself in front of the disk of Jupiter.  The shadow of Europa is near the center of the disk when the animation ends.  I created the animation in Image Ready.    Click here to go back.