Great Conjunction: How you can watch as Jupiter, Saturn align tonight

After a fast paced race to Mars and plans to return to the moon, there is still something left for science and astronomy enthusiasts in 2020, a rare celestial phenomenon —the Great Conjunction— when Jupiter and Saturn will align to form one of the brightest stars in the night sky on Monday being seperated by just one-tenth of a degree.

The planets regularly appear to pass each other in the solar system, with the positions of Jupiter and Saturn being aligned in the sky about once every 20 years. However, this year the conjunction is special as it’s been nearly 400 years since the planets passed this close to each other in the sky, and nearly 800 years since the alignment of Saturn and Jupiter occurred at night.

The rare phenomenon can be visible globally including in India between 6:30-7:30 pm. The planets will be easy to see with naked eye by looking toward the southwest just after sunset. Jupiter bigger and closer to Earth will be vastly brighter.

The conjunction also coincides with the longest day (December 21) in the year as the sun reaches a point where it appears to shine farthest to the south of Equator over the Tropic of Capricorn, marking the start of the winter solstice.

A rare cosmic event

According to Nasa, its was  Italian astronomer Galileo Galilei, who shaped the understanding of the solar system by discovering the four moons of Jupiter – Io, Europa, Ganymede, and Callisto in 1610. In that same year, he also discovered a strange oval surrounding Saturn, which was later found to be its magnificent rings. 13 years later, the two giant planets traveled together across the sky with jupiter catching up to and passing Saturn in 1623, in an astronomical event known as a “Great Conjunction.”

"You can imagine the solar system to be a racetrack, with each of the planets as a runner in their own lane and the Earth toward the center of the stadium,” said Henry Throop, astronomer in the Planetary Science Division at NASA. “From our vantage point, we’ll be able to be to see Jupiter on the inside lane, approaching Saturn all month and finally overtaking it on December 21,” he added.

How to watch the Great Conjunction

Saturn and Jupiter are easy to see without special equipment. Credits: NASA/Bill Dunford

To watch the Great Conjunction, find a spot with an unobstructed view of the sky, such as a field or park. Jupiter and Saturn are bright, so they can be seen even from most cities. An hour after sunset, look to the southwestern sky, Jupiter will look like a bright star and be easily visible. Saturn will be slightly fainter and will appear slightly above and to the left of Jupiter until December 21, when Jupiter will overtake it and they will reverse positions in the sky. You do not need special equipment to witness the phenomenion as the planets can be seen with the naked eye, however if you have binoculars or a small telescope, you may be able to see Jupiter’s four large moons orbiting the giant planet.