NASA has published the Hubble Space Telescope’s annual portrait of Saturn and its rings—and something’s awry.
Each year the vintage space telescope produces a composite photo of the “ringed planet” during Saturn’s opposition. That’s the moment when Earth—which Hubble orbits—is between the Sun and Saturn.
It’s when Saturn is in the full glare of the Sun, as seen from Earth, so it’s when we—and Hubble—get our best view of the year.
Now just past opposition, Saturn is presently brighter and bigger than usual, and its disc and rings are fully illuminated.
What’s going on in Saturn’s northern hemisphere?
The image, at the top of this article, was taken taken on July 4, 2020—so just prior to its opposition earlier this week on July 20, 2020—when the giant gas planet was 839 million miles from Earth. It was taken during summer in the planet’s northern hemisphere. It shows some a slight reddish haze over that northern hemisphere.
According to NASA, that haze may be due to heating from increased sunlight, which could either change the atmospheric circulation or remove ices from aerosols in the atmosphere.
The haze could also be a photochemical haze produced in summer on Saturn. “It’s amazing that even over a few years, we’re seeing seasonal changes on Saturn,” said Amy Simon, lead investigator of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
What’s going on in Saturn’s southern hemisphere?
Meanwhile, Saturns’s south polar region—where it’s winter, and which is only just visible in this photo—appears blue.
Saturn’s atmosphere is mainly hydrogen and helium with traces of ammonia, methane, water vapor and hydrocarbons.
Saturn’s rings (and how to see them yourself)
Hubble’s image also shows the planet’s entrancing concentric rings, which are comprised largely of ice, though scientists still don’t know how and why they formed. Sadly Saturn’s rings are now “closing” from Earth’s point of view.
Although we’re now just past opposition, Saturn and its rings are going to be at their brightest and best until August 9, 2020. Any small telescope will do for a peek, though a 150mm/6-inch telescope is recommended for a good view.
Can Hubble see Saturn’s moons?
Hubble’s annual portrait of Saturn also shows some of its 82 moons. Mimas at right, and Enceladus at bottom, are easily visible, but on this annotated version (above) it’s also possible to make-out Helene, Pandora and Epimetheus.
How to find Saturn in your night sky
It’s really easy this month. Saturn being at opposition also means it rises in the east around sunset and sets in the west at sunrise. It’s now at its best for telescopic, binocular and naked eye viewing—you can’t miss it to the left of brighter planet Jupiter.
The position of Saturn and Jupiter will change throughout the night; they will move higher in the sky, though from mid-latitudes of the northern hemisphere they never get particularly high, and it will remain in the southern night sky.
Saturn and Jupiter’s ‘Great Conjunction’
The two gas giants will have a “Great Conjunction” on December 21, 2020 when they appear to be less than 1º apart in the night sky. On that date the two planets will appear to shine as one. It will be the closest they have appeared to be since 1623.
For now just enjoy Hubble’s annual super close-up of what must surely be the Solar System’s most beautiful planet.
Wishing you clear skies and wide eyes.