Hi RC,It depends on your ppvseectire. From Earth, Io, Europa and Ganymede do, but not always Callisto. It orbits farther out, and unless Jupiter, Earth and the sun are nearly edge-on to one another, its shadow misses the planet despite its very slight orbital inclination of 0.28 degrees. If Earth were always aligned with Jupiter's equator (as we are every 6 years) all four moons would always cast a shadow on the planet. And you're right, since Jupiter's bigger, it really helps. If not for its size, you can easily see how the shadow of Ganymede would have missed the planet this evening from our ppvseectire.