Jupiter (resized 3x)

Finally got a chance to properly try my 600mm F4 lens + teleconverter last Friday. :-)

 

Here's Jupiter with (from l. to r.) Callisto, Europa, Ganymede's shadow (and the moon itself fainting visible to the right of it), and Io.

 

Another hour and I would have captured the Great Red Spot ... oh well, next time. :-P

 

Stack of 10 shots at 1020mm F6.7, final image resized 3x

Done