The giant planet reaches “opposition” on May 8 and dominates the night sky all month.

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Jupiter Planet
Credit: Universal History Archive/Getty Images

What's that bright star in the southeastern sky? If you're looking just after dusk at anytime in May, it's probably the planet Jupiter.

Shining brighter than at any point of the year, the giant planet is close to what astronomers call “opposition.” It's the best-ever time to look at Jupiter, and for anyone with even the smallest telescope, the astronomical highlight of the year.

When is the best time to look at Jupiter?

Technically that's the night of Tuesday, May 8, when Earth is exactly between the sun and Jupiter, so we see a full Jupiter. It's exactly the same as when Earth is between the sun and the moon, and see a totally illuminated full moon all night long, except that Jupiter's opposition happens only once every 13 months.

On May 10, it's also the closest Jupiter and Earth get to each other. Jupiter will be visible all night long, and highest in the sky just after midnight.

How to see Jupiter

You don't need a dark sky, nor any knowledge of the night sky, to enjoy Jupiter at its brightest and best. Rising in the southeast after sunset, Jupiter will cross the sky and sink in the west at dawn. It's in the constellation of Libra, near to its second-brightest star Zubenelgenubi.

Jupiter
Credit: STAN HONDA/Getty Images

Although it's a majestic sight with the naked eye, if you can find any pair of binoculars or a small telescope you can get a stunning close-up. In binoculars you will see a bright disc and possibly four moons — Io, Europa, Ganymede, and Callisto — arranged either side of Jupiter. If you have trouble keeping binoculars steady enough to see anything, bring your elbows in to rest on your chest, which should lessen the wobble. However, for a much better view, use any small telescope. As well as making the moons much easier to see, you'll be able to see Jupiter's cloud bands.

Where to see Jupiter through a telescope

The best way to see Jupiter close-up is through a reasonably large telescope. That's done most easily by attending an observing session run either by your local astronomy society or by an observatory.

The Amateur Astronomers Association will be at the Pioneer Works, Brooklyn on May 13, while on the west coast Griffith Observatory in Los Angeles is holding its monthly star party on May 19. The 40th annual Texas Star Party is being held at Fort Davis, Texas from May 6-13, while nearby MacDonald Observatory is staging a star party on May 8. Eagle Lake Observatory in Minnesota has a special Jupiter at Opposition star party on May 19, while Arizona's Robert Ferguson Observatory has a star party scheduled for May 12.

When is Jupiter next at opposition?

Jupiter will next be at opposition on June 10, 2019, and again on July 14, 2020 and August 19, 2021. The timing of Jupiter's opposition is caused by the differing speeds of Earth, an inner planet 93 miles from the sun, and Jupiter, which is an outer planet 484 million miles from the sun.

Jupiter takes 12 years to orbit the sun, in which time Earth orbits the sun 12 times. So every 13 months, Earth catches up and overtakes it. When that happens, Jupiter looks exceptionally bright from Earth.

However, Jupiter's opposition on May 8 is only the first of three planetary oppositions this summer. On June 27, it's Saturn's turn, followed by Mars a month later on July 27 (when it will be twice as bright as Jupiter). If you've never seen the Giant Planet, the Ringed Planet, or the Red Planet up close, this summer you'll have three chances to get to know our neighbors.