What am I seeing on Jupiter?

I am observing Jupiter at about 170x and can see a dark spot.Could this be a new hole in the cloud band or could it be the shadow of IO in transit?

Peter T2010-08-22T03:10:33Z

Favorite Answer

There was an Io transit between about 0300 and 0500 EDT on Sunday Aug 22. Since Jupiter is close to opposition, the shadow transit should have occurred at a similar time.