In reality, Saturn and Jupiter are hundreds of millions of miles apart.
“On the 21st they will appear so close that if you held a dime on edge at arm’s length, that’s how close they would be together,” Bidlack said.
From Colorado Springs, sky gazers only need to look toward Cheyenne Mountain to catch a glimpse. Elsewhere in Colorado, Bidlack said folks can look to the southwestern skies, low near the horizon.
The pair sets around an hour and a half after the sun does, about 4:39 p.m. on Monday.
The planets will begin to separate when viewed from Earth, and will eventually disappear altogether from the night sky until reappearing in the morning sky in early 2021. See more skywatching tips from NASA.