A triple dose of celestial wonder is in the stars this week as Jupiter, Mars and the moon line up for a rare captivating display in the night sky.
Called a triple conjunction, this astronomical feat in which planets or celestial objects appear close to each other is visible during the late evenings this week. And the great thing is, you don’t need a telescope or binoculars to see it, say astronomers.
“While two-body conjunctions are more common, three-body conjunctions can provide quite a visual spectacle,” said Jonathan Kemp, with Wellesley College’s Whitin Observatory, who described seeing them as a “visceral experience.”
An added bonus will be the reddish-orange giant star Aldebaran, the bull’s eye in the constellation Taurus, which will be shining brightly nearby on the same nights.
“It’s pretty, you know you can actually see two planets relatively close together along with the star that’s very close to the red color of Mars,” said Francine Jackson, an astronomer with Brown University’s Ladd Observatory in Providence, R.I. “And then with the moon right next to it, it forms kind of a nice little pattern to it.”
This celestial triangle will feature Jupiter, the brightest planet in our solar system after Venus, and on its left will be Mars. “And almost identically apart from Jupiter on the right, will be Aldebaran, the flaming eye of Taurus, the bull…So you’re looking at Jupiter stuck between two reddish objects and then with the moon directly above it, it’s a really nice scene,” Jackson said.
A less illuminated “fat, waning crescent moon” should make Jupiter and Mars easier to locate in the night sky.
When’s the best time to view this ‘triple wonder’?
The best time to start viewing the conjunction will be between midnight and 1 a.m. every night this week looking east.
The wonderful thing about this triple conjunction, Jackson noted, is that it can be enjoyed with the naked eye and without venturing far to escape any light pollution. The backyard is a fine vantage point as long as there are no large trees obstructing your view. “You do need at least to be able to see a fair amount of the eastern sky,” she added.
“After finding the moon, both Mars and Jupiter should be plainly visible, weather permitting, as the bright objects just below the moon,” Kemp said.
“If you have nothing to do at midnight or one o’clock, then go out and start looking for it,” Jackson said, adding that the trio will continue across the sky until just before sunrise at 6:05 a.m. ET. These stargazing wonders “that we can see with the naked eye are really, really beautiful to look at. You can’t miss it because of its brilliance.”
As with any stargazing, cloud cover could mask the spectacle, and tonight is expected to be partly cloudy with some sporadic clearing across Greater Boston and the rest of Southern New England.
“When you’re looking at planets, the good news is that the event can be seen over several hours unlike an eclipse where you need it to be clear for just a few minutes,” said Globe meteorologist Dave Epstein.
Jupiter and Mars actually started pairing up for a planetary conjunction on Aug. 14.
“They were about a third of a degree apart (less than the width of the full Moon), so with the naked eye, they looked very, very close to being one object,” Jackson said. According to NASA, Mars quickly pulled away from Jupiter in the following days but is still close enough to make for a beautiful view, especially with its proximity to the moon.
A triple conjunction such as this one is fairly rare, according to NASA. Jackson said the last one occurred a couple of years ago, but the next one isn’t expected until 2033.
“Conjunctions of astronomical objects are about the serendipity of geometry, and those intervals can be irregular, depending on the objects,” Kemp said. “Notable conjunctions, and especially those involving the planets of our solar system, can happen frequently, but the more objects involved, the rarer the occurrence.”
And although the trio of the moon, Jupiter and Mars will give the appearance of being quite close to together, in reality, they are still very far apart from each other. A conjunction, Kemp said, typically refers to an alignment specific to the point-of-view or reference frame of a viewer on Earth.
“In the case of this upcoming late August conjunction, the moon will be about 240,000 miles from Earth, Mars about 135 million miles from Earth, and Jupiter about 480 million miles away,” Kemp explained. “While an Earth-based observer will see the three objects apparently close in the sky, Mars will be about 600 times further than the moon, and Jupiter will be about 2,000 times further than the moon and about 3.5 times further than Mars.”
Also this week, Kemp said, stargazers might be able to catch a glimpse of a six-planet alignment in which Mercury, Mars, Jupiter, Saturn, Uranus, and Neptune will all be in the night sky at the same time.
“The planets are strung out over a larger distance, providing a wider-angle spectacle over the broader canvas of the night sky,” he said.
While Uranus and Neptune would typically require binoculars or a telescope to be visible to an observer, Mercury, Mars, Jupiter, and Saturn will be visible with the naked eye.
Kemp, Jackson and other astronomers said opportunities like these are great ways for people to take the time and explore what our natural surroundings have to offer.
“I’d like to hope that people go outside and look at it and say ‘Hey, this sky is pretty nice’ and maybe it could be the start of observing, of people kind of being aware of what’s over their head, because one of the great things about astronomy is, let’s face it, it’s free,” Jackson said. “All you have to do is go outside and look up and enjoy whatever’s up there.”
Marianne Mizera can be reached at marianne.mizera@globe.com. Follow her @MareMizera.