Shadow on Jupiter,,help for a beginner

While accounting for Jupiter's four Galilean moons I noticed another, what appeared to be a shadow of a moon, on the disc. It was about 1/4 across the disc from Europa.

Any ideas of what it is :

Tonight at 2300hrs


(please don't tell me its a spacecraft on a visit from venus :lol: :lol: )

Hi CTR,
I had a look at starry night pro and I can confirm for you that you saw the shadow of Io trailing Io itself.
Io was finishing a run across the disk of Jupiter at that point and Callisto was 1hr away from starting.


OR, then maybe it was a refugee ship on its way here from the Shoemaker-Levy impact a number of years ago

Thanks Dave

While I'd like to think it was the latter I'll reluctantly believe its the former :lol: :lol: :lol: