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Have you seen Jupiter getting brighter nightly? The Giant Planet reaches “opposition” on Monday, September 26—and its closest approach to Earth in 70 years! It’s a once-in-a-lifetime treat to view Jupiter at its best, including Jupiter’s moons. See some amazing photos and viewing tips.
Jupiter in Opposition
Great Jupiter reaches opposition on Monday, the 26th of September. The Giant Planet will be at its brightest for the entire year.
Don’t worry. There’s nothing to be concerned about! “Opposition” occurs when planet Earth passes between the Sun and a planetary object (in this case, Jupiter). The entire disk of Jupiter will be illuminated all night!
This means we Earthlings get to watch a “full” Jupiter, similar to watching a full Moon!
Image: Taken 9/14/2022. Jupiter, Europa (in transit), Io, and Ganymede. Credit: Vince Laine from Moon Township, PA.
Closest in 70 Years
There’s an added bonus this year! Not only is Jupiter in opposition but it’s also approaching its own “perihelion,” which is the closest a planet gets to the Sun in its orbit. Its perihelion will occur in January 2023.
So, as Jupiter hits its opposition on route to its perihelion, the Giant Planet is closer to Earth at this opposition than it has been since 1951! And it won’t be this close again until the year 2129 — 107 years from now. Of course, when we say close, it’s all relative! At opposition, it will be 367 million miles away. It can be as far as 600 million miles.
Bottom-line: We’ll be able to see Jupiter a whole lot better than at any time in our lifetimes. This really is a once-in-a-lifetime experience to see Jupiter at its best, as well as Jupiter’s Moons.
How to See Jupiter
Well, here it is: Just find the brightest star anytime between nightfall and midnight, and you’ll find Jupiter. Yep, that’s it. No fiddling with charts. Just look towards the east after sunset as Jupiter ascends, crosses the sky overnight, and then sets before sunset in the West.
If you want to mark your calendar, September 26 is the closest day. However, if you’re worried about weather conditions, Jupiter will be visible not only ALL night but also ALL through the month of September.
Jupiter is a giant. You could take all the other planets and double their combined masses, and you wouldn’t get the weight of Jupiter alone. The ancients got it strangely correct when they named it the king of the gods.
If you have a small telescope, use it! You’ll see the disk illuminated—striped with two dark belts. If you have a night when the stars are NOT twinkling, have a look. Jupiter’s colorful features not only belts but also white zones, small dark and white circular storms, and, most famous of all, its Great Red Spot. This giant hurricane, twice the size of Earth, is sometimes beige, but most years it’s brick red. Occasionally it’s orange. Nobody knows what causes the persistent color—probably sulfur or phosphorus compounds.
Viewing the Moons of Jupiter
Look for Jupiter’s four brightest moons which are easy to spot. Pretend you are Galileo and rediscover these tiny “stars” that he saw then —Io, Europa, Ganymede, and Callisto. They’re called the “Galilean moons” and usually look like dots in a straight line like a string of pearls.
Image: The four Galilean moons that we can still observe to this day. Credit: https://www.stellarium-labs.com
Together with Mercury, Jupiter is the only planet with essentially no tilt to its axis, which is why its moons can appear so aligned. Note: You may not see them all at once as they rotate the planet. Ganymede is the largest moon, casting the largest shadow on the planet’s cloud tops when it transits in front of Jupiter.
It was on January 7, 1610 that Galileo saw three stars lined up alongside the dazzling planet. By the 13th, he had watched them change position each night, spotted a fourth as well, and realized they were orbiting around that world.
This, 407 years ago, was no small event. At the time, Church doctrine followed the writings of Aristotle and Ptolemy and insisted that Earth is the center of all motion. For some bizarre reason, they’d made it into a religious principle.
So Galileo enjoyed no benefits after he published his startling discovery that proved that Earth is NOT the center of all motion. Instead, those little moons whirling around Jupiter caused Galileo to be brought up on charges, forced him to recant at penalty of being burned at the stake, and left him to die penniless.
Image: Callisto, Jupiter, Europa (in transit), Io, and Ganymede on 9/14/2022. Also note a non-Galilean moon, Amalthea, which is very special. Credit: Vince Laine
But fast forward to our modern times, and now those four giant moons visible through the smallest cheap telescope are called “the Galilean satellites.” So it all worked out for the bearded, cantankerous Italian, or at least for his disembodied spirit.