svetz
Works in theory! Practice? That's something else
Amateurs Spot New Impact Flash at Jupiter
An amateur astronomer has discovered a possible new impact flash in Jupiter's equatorial region. Observers may yet see the dark impact scar.
skyandtelescope.org
(Impact is looped a few times)
Looks like the impact flash is about a quarter the diameter of the earth (just a rough guess on my part as the Earth is about the size of the great red spot).