Going into the holiday season, there’s been a lot of talk, particularly on social media, about the Star of Bethlehem being visible on Monday, Dec. 21. While it’s not quite the case that the star that led the three wisemen to the site of Jesus’s birth will be making reappearance, something spectacular will be visible in the western sky for about an hour after sunset.
“On the 21st, Saturn and Jupiter are going to be in what is called a ‘great conjunction’ because they’re going to get super close to each other relatively speaking, from our point of view,” Dr. Todd Young, director of the Fred G. Dale Planetarium and professor of physics and astronomy at Wayne State College, said.
Saturn and Jupiter are already very close, but what will make Monday’s great conjunction special is that they will be the closest appearing that they will be.
“The two will be about .1 degrees apart, which means if you were to hold up a dime at arms length, they’re going to be (appearing to be) about the width of that dime apart from each other,” Young said.
To those viewing with just the naked eye, the conjunction will look like a very bright, elongated star. Young said onlookers won’t be able to miss it in the western sky.
Conjunctions happen all of the time, however, Monday’s will be very special.
“Because of the orbits of Jupiter and Saturn, they actually have conjunctions about every 20 years, so the last conjunction they had was in 2000,” Young said. “But, it was not observable because that took place in the same region of the sky as the sun, so we couldn’t see it. The last time that there was a conjunction this close that was able to be seen was in 1226 and the next time that they will be seen this close will be in 2080.”
Young said even though it will be observable with the naked eye, it will be a great event to break out a telescope, or even pair of binoculars for.
“Even with the most basic telescope, these two will be so close that they will be in the same field of view even with a high magnification. I would really encourage anyone who has that basic telescope sitting in the garage, this is the time to get it out,” he said.
With a telescope, if it’s a clear night and not too windy, the rings of Saturn should be visible and the moons of Jupiter will also be visible with magnification.
Young said the best time to view will be about 45 minutes after sunset, but he said time is of the essence.
“You don’t have much time, unfortunately, because this is all taking place in the western sky so by 6:45 they’re setting. It’s a limited time offer,” Young said.
While Star of Bethlehem is a much catchier name to draw views on the internet, Monday’s phenomenon is a great conjunction, however, Young explains why the two things are being compared.
“People keep comparing this to the Star of Bethlehem. There is speculation that the Star of Bethlehem in the past was a great conjunction of planets,” Young explained. “We know the orbits of the planets well enough that we can run the clock backwards that many years and there was a great conjunction of Jupiter and Venus back then, so that very well could be what was seen.”
Young encourages everyone to view the great conjunction Monday night. He also stated that if anyone has questions about the event or any astronomical questions, he’s happy to answer them via his email, toyoung1@wsc.edu
