IDAHO — This coming Monday kicks off Winter Solstice, the shortest day of the year, but stargazers out there will have something else to look forward to this next week with the Great Conjunction of 2020.
“Jupiter and Saturn are both orbiting the sun, and Jupiter is closer than Saturn and moving faster. So, once every 20 years, Jupiter catches up to Saturn and laps it,” said Jason Barnes, University of Idaho professor of physics.
When planets are this close together, it is known as a conjunction. For Jupiter and Saturn, this happens every 20 years.
“But this particular event on the 21st, they will be getting closer together than they usually do,” said Barnes.
A sight you won't want to miss.
“If you go out on the twenty-first and you look to the southwest horizon right after sunset, maybe a half-hour to an hour after sunset, you should be able to see Jupiter and Saturn together out in the sky," said Barnes. "They will be so close together they will be one-tenth of a degree apart, so basically a fifth of the diameter of a full moon.”
A once in a lifetime view that won't be visible again until 2080, according to NASA.
“The last time Saturn and Jupiter were this close together was when Galileo first used his telescope to look at the sky, so 400 years ago," said Barnes. "It’s a pretty cool event I’ve never seen them this close together.”
The planets will be lit up and visible from Earth with your naked eye, so there's no need for equipment.
“But, if you do have a telescope and look at them through the telescope, you'll see them both like Jupiter and its moons and Saturn and its rings and moons all in the same view,” said Barnes.
The best time to view the Great Conjunction is when the planets are closest together on Monday, December 21, after sunset.
However, you can still catch it a couple of days before and after as the planets slowly start to pass each other.