As the evenings draw in and the sun begins to set earlier each day, the fall months can offer excellent opportunities for stargazing, without the chill of winter.
Jupiter will enter opposition on September 26 this year, but what exactly does it mean when we say a planet is in opposition? How can you spot Jupiter in opposition? And in which constellation will Jupiter appear? The answers to these and more are below.
If you can still enjoy the warm weather and (relatively) clear nights, why not make the most of them with our UK full moon calendar and beginner’s guide to astronomy? And in case you missed it, we rounded up the best images from the 2022 Harvest Moon.
What is the opposition?
The opposition is essentially the planetary equivalent of a full Moon. When a planet is close to the Earth, and on the opposite side of the Earth to the Sun, we describe it as that planet is in opposition. Sunlight shining on the planet is completely reflected, just as sunlight is completely reflected from the Moon every 29.53 days in the lunar cycle.
As the outer planets orbit the Sun, Earth occasionally comes between the Sun and another planet, with all three directly aligned. Oppositions can often provide the best opportunity to observe and photograph a particular planet because of its favorable position and brightness.
At Jupiter’s opposition, the Earth will be directly between Jupiter and the Sun, and will remain in the sky above the horizon for most of the night.
Only those planets that are beyond the Earth’s orbit can be in opposition, these are Mars, Jupiter, Saturn, Uranus and Neptune. Because Mercury and Venus orbit the Sun within the path of Earth’s orbit, they can never be in opposition.
When is Jupiter in opposition?
Jupiter will reach opposition on Monday, September 26, 2022, when it will be the closest and brightest of the year, essentially creating a “full” Jupiter. The King of the Solar System will rise as the sun sets at 6:52 PM on Monday, September 26 and will remain above the horizon until it sets at 6:57 AM on Tuesday, September 27, 2022 , as seen from London (times will vary by location) .
Weather permitting, we are expected to be afforded perfect visibility of Jupiter. When Jupiter reaches opposition, the gas giant will be approximately 591.3 million kilometers (3.95 AU) from Earth.
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What will you be able to see?
To unaided observers, Jupiter will appear as a very bright point of light that, unlike stars, does not twinkle. A good set of binoculars (7x to 10x magnification) will give you a view of Jupiter’s four largest moons, Ganymede, Europa, Callisto, and Io, and a telescope will let you see Jupiter’s streaks.
How you can see Jupiter at opposition tonight © Getty Images
Jupiter’s bands, the Great Red Spot, and even the clouds can be seen through a telescope. Jupiter has a fast spin, and eagle eyes can even spot the resulting slightly squashed appearance of its bright disk.
From 18:52 on Monday, September 26, Jupiter will rise in the eastern sky, in the constellation of Pisces. As the night progresses, the planet will travel eastward and reach its peak at midnight before setting at sunrise, disappearing below the horizon at 6:57 a.m. the next morning .
If you’re interested in astrophotography or creating an animation of Jupiter, expert Pete Lawrence has put together this handy guide on how to make a planetary animation.
How can I spot Jupiter in the night sky?
Jupiter is one of the brightest objects in the night sky, making it relatively easy to spot, even without a telescope. If you have trouble with orientation, there are astronomy apps you can download; all you have to do is point your phone at the sky and the app will tell you what it is.
For those of you who prefer stargazing, look southeast after sunset. Jupiter will rise in the constellation of Pisces, which can be seen anywhere in the world, with the exception of Antarctica. Although Pisces is a large constellation, its stars are relatively dim. However, its distinctive V-shape is one of the largest star formations in the sky.
You can find Pisces by first locating the summer triangle and drawing an imaginary line from the bright star Vega and dividing the triangle perpendicular to the base, which is formed by Altair and Deneb. This line points to the head of the western fish in Pisces. Jupiter will be sitting just below the Western Pisces.
Jupiter reaches opposition on September 26, 2022 © NASA/ESA/ESO/Space Telescope Science Institute/IAU Minor Planet Center/Fabien Chereau/Noctua Software
How often do oppositions occur?
Each of the planets comes into opposition approximately every year. This is because the Earth has a faster orbit, passing between these planets and the Sun. The exception is Mars, which is around every 26 months because it is relatively close to Earth in the Solar System. Jupiter enters opposition every 13 months.
Jupiter’s 12-year cycle
Jupiter lies within the zodiac band of the sky and moves through about 1/12 of its orbit each year (a single orbit is about 12 years).
In other words, it takes Jupiter about 12 months to cross one of the zodiac constellations and move to the next. This means that Jupiter enters opposition every 13 months and the planet will pass through all the constellations of the zodiac over a period of 12 years.
Like the other planets, Jupiter travels from west to east across the night sky, against a backdrop of distant stars and galaxies. However, when in opposition, the planet also enters a period of apparent retrograde motion, when it appears to move backwards for a time.
These are the constellations in which Jupiter will appear during the next 12-year cycle:
- September 26, 2022: Pisces
- November 1, 2023: Aries
- December 6, 2024: Taurus
- January 9, 2026: Gemini
- February 10, 2027: Leo
- March 13, 2028: Virgo
- April 13, 2029: Virgo
- May 14, 2030: Libra
- June 16, 2031: Ophiuchus
- July 20, 2032: Sagittarius
- August 25, 2033: Aquarius
- October 2, 2034: Return to Pisces
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