My favorite planet, besides the one I live on, is on the rise in the low eastern sky during evening twilight. It’s Saturn and you can’t miss it.
It’s the brightest star-like object in that part of the sky. This weekend, Saturn reaches its closest approach to Earth for 2025, just under 795 million miles away, which is close for Saturn. Astronomers call this opposition. Not only is the separation in space between Earth and Saturn at a minimum but the sun and Saturn are at opposite ends of the sky, with Earth in the middle. That’s why they call it opposition. Because the sun and Saturn are at opposite ends of the sky, Saturn is available all night long, rising in the east at sunset and setting in the west at sunrise. Opposition happens every 378 days as Saturn and Earth travel in their respective orbits around the sun.
Why 378 days? That’s because in the one year that it takes our Earth to orbit the sun, Saturn moves only about 1/29th of its orbital distance around our home star. It has a much larger and slower orbit than Earth, so it takes the Earth about two more weeks to come between Saturn and the sun once again.
Saturn is by far my favorite planetary telescope target. It’s been that way since I was a kid. I’ll never forget seeing Saturn through a telescope for the first time in the early ’70s at the Woodlake Nature Center in Richfield. That was a game-changer for me as I plunged into the hobby of backyard astronomy! Even through a small telescope, you can see Saturn’s ring system. That was a real thrill for me way back when and still is now. I’m now blessed to own larger telescopes, which really put my view of Saturn over the top. Even more fun for me is being able to show Saturn off to the hundreds of folks at my stargazing programs over the years, especially the kids. I never get tired of hearing reactions like “sweet,” “awesome,” “incredible,” “holy ____,” and much more! If you’ve never seen Saturn through a telescope, now is the time.
While Saturn is still one of the best telescope treasures, it’s been a bit of a bummer the last year or so. That’s because its beautiful but very thin ring system is temporarily on edge from our vantage point on Earth. This occurs every 14 years because of the alignment of Saturn and Earth in their respective orbits around the sun. The good news is that the angle of the very thin ring system will begin to open up after this year and continue to improve over the next several years. Don’t let that discourage you, because Saturn’s still one of the best telescope treasures of the night sky. Also, make sure to stay up as late as possible to view Saturn, so it has a chance to climb higher in the sky and escape the blurring effects of Earth’s atmosphere near the horizon. Start by viewing with low-magnification eyepieces and work your way up. When you’re viewing Saturn or any other planet through a telescope, it’s important to discipline yourself to take long, continuous views. Your eye needs to adjust to the level of light coming into your eyepiece. You also want to catch pockets of less turbulent air for better views of Saturn. As with a lot of things in life, you’ll be rewarded for patience and persistence!
Like all the planets in the outer solar system, Saturn is primarily composed of a ball of hydrogen and helium gas, with other trace gases present. It’s approximately 75,000 miles, way larger than Earth’s 8,000 miles. Its hallmark, though, is its incredible, intricate ring system that spans over 175,000 miles in diameter, which is more than half the distance between Earth and its moon.
Amazingly, the ring system is less than 50 feet thick on average and is made up of billions and billions of mainly ice particles ranging in size from crystals to the size of your house. Most likely, the ice is the pulverized remains of one or two of Saturn’s ice moons that were ripped apart by the planet’s tremendous tidal forces. Eventually, the ring system will dissipate millions of years from now.
Along with Saturn’s ring system, it’s also possible to see some of Saturn’s moons, even with a small telescope. The moons resemble tiny stars surrounding the planet. The brightest and biggest is Titan, over 3,200 miles in diameter. That’s larger than the planet Mercury. Enceladus, one of Saturn’s much smaller moons, is a strong candidate for possible life under its surface. The Cassini spacecraft during its 13 years orbiting Saturn detected geysers of water shooting out of Enceladus before it purposely plunged into Saturn at the end of its very successful mission.
Enjoy the rise of Saturn this autumn! Every night, it’ll start out higher and higher in the southeastern skies as evening darkness sets in.
Starwatch programs
Monday, Sept. 22, 7:30-9:30 p.m., River Bend Nature Center in Faribault, Minn. For more information and reservations, call Faribault Parks and Recreation at 507-334-2064 or visit www.ci.faribault.mn.us/219/City-Enrichment-Programs.
Tuesday, Sept. 23, 7:30-9:30 p.m., Paperjack School in New Richmond, Wis. For information and reservations, call 715-243-7421 or visit newrichmond.ce.eleyo.com/ce.
Thursday, Sept. 25, 7:30-9:30 p.m., in Northfield. For information and location call 507-664-3649 or visit northfieldschools.org/communityeducation.
Friday, Sept. 26, 8-10 p.m., Big Marine Park Reserve near Marine on St. Croix. For information and reservations, call 651-430-8200 or visit www.co.washington.mn.us/index.aspx?NID=532.
Mike Lynch is an amateur astronomer and retired broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and adventurepublications.net. Mike is available for private star parties. You can contact him at mikewlynch@comcast.net.
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