On December 21st, 2020, the winter solstice, Jupiter and Saturn will be closer together in the night sky than they have in almost 400 years. On any night when Jupiter is visible, with a decent pair of binoculars (a magnification of 8x to 10x), you can see its four moons. If any of the moons happen to be behind Jupiter that night, just come back out the next night and you'll be able to see it. The moons all orbit considerably faster than Earth's moon does.
This rather blurry picture was taken on December 3rd by holding my cell phone up to a scope magnified to about 50x. It was tricky because my tripod no longer works properly, so I had to use one hand to aim the scope and the other hand to line up the phone with the lens. With a direct view (no cell phone) you can clearly see some of the marbling on Jupiter's surface. But even in this low quality picture you can still see three of the moons. To the right of Jupiter there's a speck of light. That's Europa. Close by on the left is the volcanic moon of Io. Ganymede happens to be behind Jupiter in this shot, but way out on the far left, that little white pixel is Callisto. Some day humans will go there.
The link above is a good one for determining which little dots next to Jupiter are which moons, since they change position a lot from night to night. Around the time of the solstice both Jupiter (plus all four moons) and Saturn should be visible through the same scope view. A magnification of 10x, typical for binoculars, is enough to notice a distinct oval shape to Saturn, but not really its rings. After about 20x magnification you can start to see that detail. Imagine a detailed view of both gas giants at the same time!
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