Saturn Will Look Naked in the Night Sky This Weekend

Stargazers with backyard telescopes may notice something amiss in the night sky this weekend as a rare planetary alignment produces a mind-boggling optical illusion.

On Sunday, November 23, Saturn’s iconic rings will almost completely disappear. Don’t worry, the billions of chunks of rock and ice that circle this gas giant won’t actually be gone, but they will temporarily look invisible to us Earthlings. That’s because Saturn will align with Earth so that its rings face us edge-on. Since they’re so thin, we’ll no longer be able to see them clearly.

This happens every so often due to the fact that Saturn leans at an angle of 26.7 degrees. That means its rings shift up and down as it orbits the Sun. When Saturn’s rings are visible to Earth—which they are most of the time—we’re looking at the flat plane of the rings tilted toward us, making them appear broad and bright in the night sky.

This weekend’s alignment won’t result in a total vanishing of Saturn’s rings, but they will appear to narrow to less than 1% visibility before the relative positions of the two planets make them appear to widen out again, according to the New York Times.

A rare cosmic illusion

Saturn’s ring system extends up to 175,000 miles (282,000 kilometers) out from the planet. Relative to that width, they’re extremely thin, with a vertical height of only 30 feet (10 meters) in the main rings.

The edge-on alignment between Earth and Saturn occurs every 13 to 15 years when Earth passes through Saturn’s ring plane. This is actually the second time it’s happened this year, with the first instance occurring on March 23.

During one of these events, Saturn’s rings typically remain invisible for about a week. After they reappear later this month, we won’t get to see this illusion again until October 15, 2038, according to NASA.

Though these periodic vanishing acts are nothing more than a trick of angles, Saturn is actually losing its rings, albeit very slowly. The material that makes up the rings is being pulled into Saturn by its own gravity as a dusty rain of ice particles. Data collected by NASA’s Cassini spacecraft, which flew through Saturn’s rings in 2017, suggests they could disappear for real in 100 million years.

You certainly won’t be around to see that happen, but if you’d like to experience this weekend’s ring plane crossing, here’s what you need to know.

How to see Saturn naked

Saturn will be visible in the southeastern sky after sunset over the weekend, but you’ll need to use a telescope to see it without its rings. Any small backyard telescope will do.

The rings will look thinnest at 7 p.m. ET on Saturday, according to the New York Times, but you’ll be able to see the edge-on effect if you look before 3:30 a.m. local time on Saturday or Sunday, when Saturn sets from the night sky.

If you want to see the rings in their full glory, you’ll have to wait for the edge-on effect to dissipate. They will gradually get wider over the coming months, reaching their greatest apparent width in late 2027.