Just last month stargazers pointed their peepers to the sky for a glimpse of the ‘Christmas Star’. Now, high off the spectacle 400 years in the making, space enthusiasts will be gifted another extraordinary display! This weekend, see Jupiter, Saturn and Mercury light up the night in with a rare three-planet conjunction.
The solar system’s largest planets may have drifted apart since the December event, but they’re still very visible to those looking hard enough.
Since last month, Jupiter and Saturn treated skywatchers to a spectacular, once-in-a-lifetime “,” when they were closer in the night sky than they had been since medieval times. Now, as our solar system’s two largest planets continue to drift apart, they will be joined by a third — Mercury — forming a rare three-planet conjunction.
A triple conjunction is traditionally defined as two planets meeting each other three times in a short timeframe but NASA has also used the term to refer to three planets meeting. A planetary trio is defined by planets within a circle with a diameter less than 5 degrees in width — which can be visualized as three fingers held together at an arm’s length, according to EarthSky.
The last one occurred in October 2015.
Jupiter and Saturn have been slowly drifting apart since theirin December, but Mercury is just now coming into view, forming the planetary triangle.
“From Friday evening to Monday evening, the planet Mercury will appear to pass first by Saturn and then by Jupiter as it shifts away from the horizon, visible each evening low in the west-southwest and setting before evening twilight ends,” NASA said.
Planetary trios are relatively rare, although nowhere near as special as the recent great conjunction. Mercury, Venus and Jupiter will meet in the sky on February 13.
After that, another triple conjunction won’t occur until April 2026, when Mercury, Mars and Saturn meet, according to EarthSky.
Over the next few days, in addition to the 5th and 6th planets (which just appear as two really bright stars to the naked eye), the sun’s neighbour will also move across our sky.
Nasa said: “From Friday evening to Monday evening, the planet Mercury will appear to pass first by Saturn and then by Jupiter as it shifts away from the horizon, visible each evening low in the west-southwest and setting before evening twilight ends.”
You should look towards the Capricorn constellation to try and spot the planets at twilight over the next few days.
Night sky scanning apps can be useful to download if you need to be pointed in the right direction of a constellation.
Some of the apps can even point out planets to you.
How to watch
The planetary trio can best be spotted at dusk, from Friday through Monday. All three will be visible low in the western sky, close to the sunset point on the horizon, EarthSky said.
On Sunday, January 10, the three planets will be closest together, fitting inside a circle with a diameter of 2 1/2 degrees at 19:00 UTC.
Clear conditions will be needed to spot the planets, but they will be visible together for several days. As always, it is important to find an area away from bright city lights for the best viewing conditions.
Binoculars will come in handy for spotting the trio clearly, but they will also be visible to the naked eye. Another way to improve your experience is to view the event from a high vantage point, with a very clear view of the horizon line.
Jupiter will be the brightest of the planets, followed by Mercury, then Saturn — making it the most difficult to spot. It’s important to look for the planets in the 30 minutes after sunset — any later, and they will fall below the horizon line.
Following their conjunction, mercury will continue climbing higher in the sky, while Jupiter and Saturn will sink, soon fading from view altogether. Mercury will reach its greatest elongation on January 24.
For the first time since October 2015, you have a chance in the coming evenings to view a planetary trio, or three planets bunched together on the sky’s dome. At evening dusk – on January 8, 9, 10 and 11, 2021 – watch for the now-famous planets Jupiter and Saturn, fresh from their December 21 great conjunction and still close together. The third planet, Mercury, is just now coming into view. All three worlds pop out low in the west, close to the sunset point on the horizon. Jupiter will be the brightest of the three, followed by Mercury and then Saturn. Start watching them tonight and watch them move in relationship to each other!
To see this planetary triangle, NASA recommends that you use a pair of binoculars or a telescope for a clear view. If you have neither of those things, don’t fret, as we said you can also see them by simply lifting your head. You won’t see Saturn’s rings or anything, but it’ll still look pretty cool.
10/10 would recommend, friends! The last time this particular alignment happened was in 2015, so it’ll be quite some time until we see it again! Check it out!
When: All weekend (Planets will be closest on Sunday, January 10th)
Time: Right after sunset / Right before sunrise
On January 8 and 9, bright Jupiter will be at the top of the gathering. The sky chart at top is for January 9, 2021, when fleet-footed Mercury will pass to the south of Saturn.
The tightest grouping of these worlds will be on January 10.
Then Mercury will swing to the south of Jupiter on July 11, as shown on the chart below.
Depending on your sky conditions and use of optical aid (binoculars), you should be able to watch this planetary trio for several days to a week.
However, stargazing is best when you’re in a very dark location and looking at your phone screen can affect your ability to adjust your eyes to the dark.
You may need binoculars to see all three planets.
Jupiter will be the brightest so if you spot that first you should find the other two nearby.
Around 45 minutes after sunset is probably the best time to look for the planets low down on the west-southwest horizon.
You’re also better going to somewhere that has an unobstructed horizon view if you can.
Bear in mind that Saturn will stay below the big bright Jupiter for the conjunction but Mercury will progressively appear higher as the nights continue.
Cloudy skies may ruin your chances of spotting the celestial trio.
By definition, a planetary trio consists of three planets fitting within a circle whose diameter is less than 5 degrees in width. For reference, three fingers held together at an arm length approximates 5 degrees. Given that a typical binocular field of view spans 5 degrees or more, binoculars come in super handy for viewing a planetary trio. If you spot Jupiter with the eye alone, but not Mercury or Saturn, aim binoculars at Jupiter to see the threesome taking stage in a single binocular field!
At their closest, the planets of this planetary trio will fit inside a circle with a diameter of 2 1/2 degrees on January 10 (at 19:00 UTC; translate UTC to your time).
To maximize your chances of catching these worlds, find an unobstructed horizon in the direction of sunset. All the planets of this planetary trio will follow the sun beneath the horizon by nightfall, so it’s imperative that you start your search no later than 45 minutes after sundown. Jupiter is about 2 1/2 times brighter than Mercury, and 10 times brighter than Saturn (which makes Mercury about 4 times brighter than Saturn).
Although all these worlds are bright – especially Jupiter – they’ll be contending with the afterglow of sunset. You might need your binoculars to catch one or two of these planets, especially Saturn.
Live in the United States or Canada? Find out when Mercury, Jupiter and Saturn set in your sky via the Old Farmer’s Almanac.
From virtually anywhere in the world, find out the setting times for Mercury, Jupiter and Saturn via TimeandDate.com.
Here’s what’s on tap for the evenings between January 9 and 11:
January 9, 2021 (21:00 UTC): Mercury passes 1 2/3 degrees south of Saturn
January 10, 2021 (19:00 UTC): Planetary trio fits inside 2 1/2-degree circle
January 11, 2021 (11:00 UTC): Mercury passes 1 1/2 degrees south of Jupiter
Day by day, Mercury will be climbing upward, away from the afterglow of sunset, while Jupiter and Saturn will be sinking toward the sun. Jupiter and Saturn will soon fade from the evening sky. Mercury, in the meanwhile, will soar to its greatest eastern (evening) elongation on January 24, 2021, so Mercury should be in good view for weeks to come!
This planetary trio on January 10, 2021, presents the first of two planetary trios in in the year 2021; and the first of four planetary trios in the 203rd decade or the period from January 1, 2021, to December 31, 2030:
January 10, 2021 (Mercury, Jupiter, Saturn)
February 13, 2021 (Mercury, Venus, Jupiter)
April 20, 2026 (Mercury, Mars, Saturn)
June 16, 2028 (Mercury, Venus, Mars)
Bottom line: For a sky watching challenge, try spotting the planetary trio of Mercury, Jupiter and Saturn around January 8, 9, 10 and 11, 2021. You’ll find a second planetary trio – Mercury, Venus and Jupiter – in the February 2021 morning sky.
- Bran writes mostly on science and is an avid reader and writer of popular science. He brings sciency a literetic emphasis bring it to mainstream media for all.
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