Jupiter at opposition: You need to see the biggest planet at its brightest
Move over, Mars.
If the planets are celebrities of the celestial world, then Jupiter is Beyoncé — the biggest star is a sky full of shimmering objects of wonder.
August skies have already been graced by the planet Saturn in opposition, and now it’s Jupiter’s turn. This vermilion-hued planet is both the largest and the fastest-spinning planet in our solar system, twirling at 28,148 miles per hour. A Jovian day only lasts about ten hours, yet the planet is 318 times more massive than Earth, and 2.5 times more massive than all the other planets in our solar system combined.
This astonishing world is among the easiest planets to spot in the night sky. And soon it will appear even brighter.
What Jupiter “in opposition” means
A planet “in opposition” is when it is at its closest point to Earth while directly opposite the Sun, creating a few hours of perfect alignment between the three bodies — with us Earthlings in the center. This relative proximity to Earth means that the planet, already a sight to be seen on other summer nights, will be at its biggest and brightest in the night sky all year.
Only planets further from the Sun than Earth — Mars, Jupiter, Saturn, Uranus, and Neptune — come into opposition. This is because opposition only occurs when the more distant planet is at its closest point to the Sun while also aligning with the Earth.
Most planets will move into opposition at least once per year — Jupiter, for example, went into opposition in July of 2020. For Mars, the closest planet to Earth that is also more distant to the Sun, opposition occurs only once every two years. Mars last went into opposition in October 2020, and it should next be at opposition in December 2022.
When will Jupiter be in opposition?
As the Sun sets on August 19, Jupiter will be in peak opposition within the constellation Capricornus. For East Coast Americans, that’s 8 p.m. Eastern, on August 19.
The Moon is currently waxing, building up to an August 22 Full Moon, so you will also be able to see our closest natural satellite shine that night.
The planet will appear unusually large, like an overly bright star that will outshine most everything around it — even the also visible Saturn. From this distance, the planet will not look very red, but if your eye is drawn to a strangely bright spot in the sky then it’s probably Jupiter.
Here’s when some of the other gas giants are in opposition in 2021:
- Neptune: September 14 at 5:12 a.m. Eastern
- Uranus: November 4 at 7:49 p.m. Eastern
How to see Jupiter in opposition
This titan of our solar system will be visible to the naked eye, and fairly easy to spot if it’s a clear night. It’s also the brightest planet in our night sky, outshining Saturn by about 18 times.
The only orb that might compete with Jupiter for attention is the Moon, which will be a waxing gibbous that night. With a pair of binoculars, Jupiter’s disk shape, plus its moons, will become clearer.
On the East Coast, Jupiter will be visible and in opposition from August 19 at 8:38 p.m. until August 20 at 5:30 a.m.
At 1:04 a.m., it will reach its highest point in the night sky.
How to see Jupiter’s Great Red Spot
Spotting the Spot — a whirling vortex of storms nearly twice the size of Earth — isn’t the easiest task, despite its colossal size and infamy. You will need patience and the willingness to try and fail a couple of times — but you can do it.
Since the planet is so far from Earth — 373.48 million miles — you will need a telescope with at least a four-inch aperture to see the Spot. Filters, particularly light green and dark blue ones, can also help to bring out the magnificent splotch. Dark skies uninterrupted by light pollution or obstacles are crucial here, and you need to be able to collimate or align the mirrors, on your telescope (the trial and error referenced above).
The Great Red Spot is an omnipresent storm in Jupiter’s southern hemisphere, characterized by swirling crimson clouds. It’s evolved and changed in size over the years, since long before it was first identified in 1665. The planet also features another storm, White Spot Z, which is a turbulent vortex in its atmosphere.
How to see Jupiter’s moons
The solar system’s most massive planet has an equally impressive count of 79 moons, and you can spot the four largest moons using a telescope or binoculars while the planet is in opposition on August 19.
The four most-easy to spot moons are:
- Ganymede — the largest moon in the solar system
- Europa — one of the worlds that scientists believe may be able to host life
These heavenly bodies are also called Galilean satellites for the champion of heliocentrism himself. You might not get quite as good a view as them as of Jupiter, but you’ll notice several specks distinctly hovering near the bright non-star.
When Jupiter is visible at night
If you can’t get outside on August 19 to see Jupiter in opposition, don’t worry. The planet Jupiter is visible in the night sky for many weeks leading up to and following opposition.
Starting in July each year, Jupiter can be spotted with the naked eye and it will be visible in the night sky until December.
The key is to get outside and look up earlier rather than later in the night — if you are on the East Coast, then the prime viewing time is 8 p.m. Eastern — or whenever it gets dark in your time zone.