Back to: Weekend Sky Report
July 10, 2020
The largest planet in our solar system is clearly visible late at night. It rises to the southeast just after sunset, and it’s highest right around 2am, so if you’re up late, go out and look. By the way, most decent binoculars and almost any telescope--even a toy telescope should show you the four Galilean Moons, Ganymede, Io, Callisto, and Europa. They’re the four largest of Jupiter’s 70+ natural satellites, and Ganymede is the most massive moon in the entire solar system. The moons will look like four stars flanking the planet on either side, though you may not see all of them.
Jupiter is very bright right now, but it will technically be at its brightest this coming Tuesday when it’s at opposition, meaning the Earth is directly between Jupiter and the Sun. Now, that said, you probably won’t notice any difference between observing Jupiter tonight versus Tuesday night. But if you do look at Jupiter on Tuesday night, you might see one of its most famous features… the Great Red Spot.
Jupiter spins faster than any other planet. It completes a rotation every 10 hours. Because the Great Red Spot is a single feature on the planet, you have to go out at just the right time to see it. Lucky for us, 11pm eastern time Tuesday night will give us that opportunity. At that time, the Great Red Spot will be dead center. And while it may be called the Great Red Spot, it's more of a pale orange these days, so it’s hard to contrast against the whites and browns of the cloud belts unless you know where to look. And don’t get frustrated if you don’t see it. You need good observing conditions and a decent telescope with lots of magnification to get a good enough view.
But if you see it, you’ll be looking at a hurricane the size of Earth that, for all we know, has been raging for more than 300 years.