Celestial News: Giant planets dominate September skies
For Steamboat Pilot & Today
Our solar system’s two giant planets, Jupiter and Saturn, are passing close to Earth this month and will shine big and bright in our evening sky.
Jupiter and Saturn, like all of the outer planets, are closest to Earth during their oppositions. That’s when the Earth passes between the planet and the Sun.
Saturn was closest to the Earth on Aug. 14 when it reached opposition, 823 million miles away, in the direction of our constellation Capricornus. Saturn is hanging out near two little stars, named Deneb Algiedi and Nashira, in the tail of the Sea Goat.
The whole month of September will be a great time to pull out your telescope and explore Saturn. A telescope of any size will reveal the planet’s beautiful icy rings, as well as its largest moon, Titan. Titan looks like a tiny orange star, right beside Saturn. It is the second largest moon in our solar system and the only moon that has a thick atmosphere and lakes of liquid methane on its surface.
Jupiter will reach opposition and be closest to Earth on Sept. 26. It comes to opposition every 13 months. However, not all oppositions of Jupiter are created equal.
Like Earth’s orbit, Jupiter’s orbit is an ellipse that brings it closer to the Sun (and Earth) on one side and farther from the sun (and Earth) on the other side. An opposition that occurs in a year when Jupiter is closest to the sun, as it is in 2022, is called a perihelic opposition and it puts Earth and Jupiter as close together as possible.
When the giant planet Jupiter reaches opposition on Sept. 26, it will be only 369-million miles from Earth, the closest it has come to us since September 2010.
Jupiter requires 12 years to orbit the sun, so it spends approximately one year moving through each of the 12 constellations of the zodiac. This year, Jupiter is moving through the constellation Pisces, the Fish, just below four bright stars that form the Great Square of Pegasus.
To see the two giant planets this month, face the direction southeast at around 11 p.m. in early September and 9 p.m. in late September. Dazzling Jupiter will be obvious as the brightest object in the sky.
Locate fainter Saturn about two hand-spans to the west (right) of Jupiter. Saturn looks fainter than Jupiter because it is a smaller planet and lies at over twice the distance of Jupiter.
Watching Jupiter from night to night with a backyard telescope is fascinating. In addition to its dark cloud stripes and Great Red Spot, there are four planet-sized moons that change their positions around Jupiter every night.
Famed Italian astronomer Galileo Galilei discovered these four moons with his little 1-inch telescope in the year 1610. Their names are Io, Europa, Ganymede and Callisto. Any telescope will allow you to watch these moons as they whirl around the giant planet, and this year’s perihelic opposition offers the perfect opportunity to give it a try. You won’t see Jupiter any bigger or brighter until 2034.
For information about astronomy-related events in Steamboat Springs, including public star parties at CMC’s Ball Observatory, contact physics and astronomy instructor Paul McCudden, at firstname.lastname@example.org or 970-870-4537 or visit the SKY Club web page at http://www.coloradomtn.edu/skyclub.
Jimmy Westlake is adjunct Professor of Physical Sciences at Colorado Mountain College and former Director of the Rollins Planetarium at Young Harris College in Georgia and the St. Charles Parish Library Planetarium, in Luling, Louisiana. His “Celestial News” column appears monthly in the Steamboat Pilot & Today newspaper. Check out Jimmy’s astrophotography website at http://www.jwestlake.com.
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