A rare triple-conjunction of Mercury, Jupiter, and Saturn will light up the sky forming a planetary triangle that will be visible to the naked eyes in clear weather conditions from January 8 to January 11. The conjunction will appear right after sunset, towards the lower western sky.
“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,” said the National Aeronautics and Space Administration (NASA).
According to EarthSky, a planetary trio is defined by planets that are within a circle with a diameter whose width is less than 5 degrees, which can also be visualized as three fingers that are held together at an arm’s length.
The traditional definition of ‘triple conjunction’ is when two planets meet each other three times within a short time. Although NASA has used this term to refer to the meeting of the three planets.
Triple planetary meetings are relatively rare and after the ‘great-conjunction’ of Saturn and Jupiter took place in December 2020, Mercury has entered the view forming the triangular meet. The three planets will come closest in the sky on January 10. They will fit inside a circle with a diameter of around 2 ½ degrees at 19:00 UTC (12:30 am IST). Out of the three planets, Jupiter will be the brightest, positioned at the top of the triangle while Saturn will be the dimmest and Mercury will appear to be the lowest in the sky, forming the base of the triangle.
Observers will see the triple-conjunction with naked eyes in areas away from city light and relatively darker areas given that the skies are clear. They can also observe the triple-conjunction with a cheap telescope or a pair of binoculars. Even with a cheap backyard telescope, observers will be able to see the larger moons of Jupiter. However, observers must make sure to witness the three planets at the right time as they will disappear from view after around 30 minutes or an hour after sunset.
After the triple conjunction, Mercury will climb higher in the sky, and the other two planets-Jupiter and Saturn will sink, exiting from the view. On January 24, Mercury will reach its greatest elongation.
Another triple planetary meeting will be seen in the sky on February 13, where Mercury, Venus, and Jupiter will meet. However, the next triple conjunction will be seen in April 2026 with Mercury, Mars, and Saturn meeting together.