This one came very close to being a double transit. But just as Europa breaks the limb to the right, Io just starts to enter from the left.The 2 shadows do, however, transit the disk together. Only a few pixels would have made a double planet/ shadow transit. Oh well. This was shot on 05/19/2017. Time starts at 02:51 UT and ends at 04:43 UT.

Copyright: John Cox