GRAND RAPIDS, Mich. (WOOD) — A rare conjunction of Jupiter and Saturn will take place on the winter solstice, creating what some are calling a “Christmas Star.”
Experts describe a conjunction as two things lining up together, similar to the hands on an analog clock each hour.
In this case, Jupiter and Saturn will be lining up together in the night sky. It’s a phenomenon that happens every 20 years.
This year’s conjunction has a few features that make it a bit more rare.
“Those once every 20 year conjunctions are called great conjunctions because of their rarity, but when two planets line up, it’s usually within one or two degrees in the sky and they can both be seen as distinct objects with the naked eye,” said Dave DeBruyn, professor emeritus at the Chaffee Planetarium and longtime member of the Grand Rapids Amateur Astronomical Association.
“Once in a very, very long interval, they line up so perfectly that you can’t distinguish them as two objects with your naked eye alone,” DeBruyn continued.
According to DeBruyn, the last time an alignment this close occurred was in 1629, almost 400 years ago. Viewers will not have to wait another 400 years for the next alignment like this to occur.
“We are in a curious moment in the history between Jupiter and Saturn,” said Larry Molnar, professor and Observatory Director in the Physics and Astronomy Department at Calvin University. “The next time this will occur is only 60 years away; for younger folks, you might get another shot at it.”
West Michigan is typically cloudy in the winter months, which makes stargazing difficult. A clipper system is forecast to bring clouds and light snow on the evening of the winter solstice.
To escape the cloud cover and see this event, head south. Clear skies are forecast for south and central Illinois and Indiana. Southwest Ohio may also be able to break out of the clouds.
Viewers can take advantage of any breaks in the clouds between Sunday and Wednesday. Since the planets move slowly, the view will still be spectacular, even if you can’t see it on the day of the actual conjunction. Spectators will want to look low on the horizon in the southwest during the evening to catch the conjunction.
“It’s important that you understand that you do not need a dark sky for this,” DeBruyn said. “What you need is a very clear horizon because there’s going to be built-in light pollution from the twilight. By the time the twilight glow fades completely to night, the two planets will be almost setting.”
Molnar explains the sight will be bright, but the rest might depend on how good your eyes are.
“They might come so close that you can’t distinguish them; I think we should see this as an eye exam,” Molnar said. “I think a second thing that’s cool, beyond the eye test, is just to see these two very different worlds in the same place at the same time. When we teach astronomy courses, we have a chapter on Jupiter and we have a chapter on Saturn, but the universe is one thing, even if we tend to categorize it. This is an amazing reminder when we can see them both together.”
Anyone who has a low-powered telescope should bring it out. Clouds will likely complicate things, but any moments of clearing could lead to a once-in-a-lifetime view of the “Christmas Star,” a bright light at the end of this dark year.