WINONA Minn. – If skies are clear Tuesday evening, Winona State University astronomer Jennifer Anderson says you can be in for a once every 400 years treat. It’s the conjunction of the giant planets Jupiter and Saturn. After sunset, 4:45 to 6:15 p.m., look southwest. Jupiter will move in front of Saturn in an unusually bright spectacle. For a real treat, she said, look through binoculars to see each of the planets, plus a few little bright dots to either side of Jupiter – the Galilean moons.
IN LINE. The Sun and planets are oversize in this schematic to illustrate conjunction compactly. Image: Planetary Society.
Quick astro lesson
Jupiter takes just 12 years for Jupiter to go around the Sun once, and just under 30 years for Saturn. Not often is that the planets are in the same location of the sky from Earth’s vantage point. Generally, there is a conjunction every 20 years, but depending on the orbits of Earth, the apparent distance between them varies a lot. This week, however, they are exceptionally close. The last time these two planets were so close was almost 400 years ago. Unfortunately, the conjunction back then came in daylight on Earth and no one was able to see this event. in a sense, this hasn’t happened jn 800 years, Anderson said.