It's almost time to bid a fond farewell to the showpiece of the solar system: the magnificent ringed planet Saturn. For many observers, Monday will likely bring the final opportunity to make a positive identification of the planet, as it will be in close proximity to a slender crescent moon, two days past new phase and just 5 percent illuminated. Wait until about an hour after the sun has gone down before concentrating your gaze low toward the southwest horizon.
The moon will be hovering only about 7 degrees above the horizon. Your clenched fist held at arm's length measures roughly 10 degrees in width, and that thin lunar arc will appear less than one fist up. Once you see the crescent, you should take note of a solitary bright "star," shining with a yellowish-white hue, to the left and a bit lower than the moon. That will be the "Lord of the Rings" — the planet Saturn itself. Before you attempt to make a sighting, make sure there are no tall trees or buildings to obstruct your view of these two celestial bodies. Both will remain in view for about another hour before they disappear below the horizon. [The Brightest Planets in November's Night Sky]
Of course, these objects are not actually right next to each other; the alignment on Monday is merely an illusion of perspective. Saturn is currently situated 1.02 billion miles (1.63 billion kilometers) from Earth. The moon, on the other hand, is more than 4,000 times closer, at 251,800 miles (405,000 km) away. Interestingly, less than a day after its moment with Saturn, the moon will arrive at apogee, its farthest point in its orbit relative to Earth.
You can only see Saturn's famous rings with a telescope. You'll need an eyepiece with at least 30-power magnification. However, Saturn now appears so low in the sky once it gets sufficiently dark that our atmosphere, which appears so much more turbulent near the horizon, will likely make Saturn's image appear to "boil" or become somewhat distorted. You should really wait until you can see Saturn at a higher altitude in a dark sky to search for its rings.
Unfortunately, you're going to have to wait awhile for that.
During the next couple of weeks, Saturn will continue to drop progressively lower, eventually getting swallowed up by the bright evening twilight. It will arrive at solar conjunction — its closest approach to the sun from Earth's perspective — on Dec. 21, transitioning into the morning sky. The very same day, the sun itself will arrive at the winter solstice, the low point of its track across the sky, as well as Saturn's southernmost point in its 29.5-year orbit. The planet will slowly emerge back into view during the second week of January, rising more than an hour before the sun. But it won't be until sometime in late March or early April that Saturn will gain enough altitude in the predawn sky for observers to get worthwhile views of the great ringed beauty. [Saturn's Rings Just Got the Ultimate Close-Up from Cassini (Photos)]
A final note: On Monday, Mercury will be hovering near the west-southwest horizon, directly below the moon and Saturn. And on Nov. 28, use binoculars to scan near the west-southwest horizon to find Mercury about 40 minutes after sunset, along with Saturn to its lower left. Mercury will glow almost twice as bright as Saturn.
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmer's Almanac and other publications, and he is also an on-camera meteorologist for Verizon Fios1 News, based in Rye Brook, New York. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.