With A Tip Of Its Rings, Saturn Greets Earth On Opposition Day

The north face of the rings are tipped nearly wide open toward Earth this year, making for wonderful views of the planet through a small telescope. Notice that Saturn’s south polar region barely pokes out below the ring plane. This is a fun detail to try and see in a telescope. Credit: Anthony Wesley

Saturday is truly Saturn’s day this year. We mark the ringed planet’s opposition today, the time when it’s closest to Earth and brightest for 2014.

Opposition occurs when Earth passes between Saturn and the sun. When both planets lie on the same side of the sun, they’re almost 175 million miles closer than when they’re on opposite sides. That translates to a bigger, brighter Saturn. Because Saturn travels a little ways around its 29.5 year orbit every year, Earth requires about 13 days to catch up to it at each succeeding opposition. We’ll line up again next year on May 23.

Earth and Saturn are lined up with the sun today and 173 million miles closer than they’ll be in about six months when Saturn is in conjunction with the sun. Illustration: Bob King

The word opposition refers to Saturn being opposite the sun in the sky, rising when the sun sets and setting at sunrise. In a word, it’s visible all night long. Just about anytime you feel like pointing your telescope Saturn’s way, it awaits your gaze.

But before we talk telescope views, let’s take a minute to pinpoint the planet’s location in the evening sky. While it rises at sunset, it doesn’t clear the low trees until about an hour and a half later. Skywatchers at mid-northern latitudes will find it low in the southeastern sky around 10 o’clock well to the lower left of Mars, due south at that hour.

This map shows the sky around 10 p.m. local time tonight May 10 facing south-southeast. Saturn is smack in the middle of the dim constellation Libra below and to the left of Mars and Spica. Stellarium

Tonight the gibbous moon won’t be far from Mars, making it exceptionally easy to find the Red Planet. Swing down to the lower lower left of Mars to spot Saturn. You shouldn’t have trouble spotting it – at magnitude +0.1 it’s nearly as bright as Vega and a pale yellow-white. The ring bearer’s out all spring and summer, so there will be many opportunities to see it.

The ring bearer calls the dim zodiac constellation Libra the Scales home in 2014. Because the moon’s waxing toward full, it’s tricky at the moment to see Libra’s dim stars. Wait till after May 16 for a better view. Maybe then you’ll notice the whimsical “Saturn Cross” like I’ve been seeing the past couple weeks.

A whimsical “Saturn Cross” formed from Libra’s brightest stars with Saturn at its center. Libra precedes the gangly Scorpius the Scorpion with its bright star Antares. Viewing time shown is 1 a.m. in mid-May. Stellarium

The “Cross”, which just happens to be oriented north-south like the constellation Crux a.k.a. ‘Southern Cross’, is simply a different way to see Libra’s four most prominent stars. Saturn marks the center of the crossbeam.

If you’ve never seen the real Southern Cross, this might serve as a cheap, no-airplane-travel-required substitute. Mostly I bring it up as an easy way for you to add a new and rather faint constellation to your life list.

As Saturn travels around the sun in its 29.5 year orbit, we see one side of the rings for about 15 years, followed by an edgewise presentation. The rings – made of dirty water ice – are huge at some 155,000 miles wide (250,000 km), but they’re only about 30 feet thick and virtually disappear when seen edge-on.

That last happened in 2009. Since then they’re re-opened with the north face visible for some 15 years.

Saturn on April 6, 2014. Its clouds belt are less contrasty than Jupiter’s and except for the prominent north equatorial belt not easy to see. A small telescope and magnification as low as 30x will show the rings. Higher power will show the wide B-ring and thinner, outer A-ring. Also visible is the dim C-ring, the dusky band in the foreground crossing in front of the planet. Credit: Efrain Morales Rivera

This year the ring plane’s tipped open 21-22 degrees, nearly the maximum of 27 degrees which occurs in 2017. A large tip exposes lots of ring ice particles to sunlight, boosting the planet’s brightness.

Views of Saturn at different ring plane inclinations taken by the Hubble Space telescope. Rings are labeled in the top image. Credit: NASA/ESA

That’s all good news for both visual and telescopic observation. Even a 2.4-inch telescope will show the rings, with a larger instrument providing a brighter, larger picture and sharper resolution of the three brightest rings. I love the planet’s subtle colors through the eyepiece – the globe looks pale brown or butterscotch to my eye and the rings distinctly brighter and whiter.

Saturn and its brightest moons around 10 p.m. CDT tonight. Titan is brightest at magnitude 9 and very easy to see. North is up. Credit: Meridian software

Small scopes will also show the brightest moons including Titan, Rhea, Dione, Tethys and Iapetus. To find where the moons are on a given night and time, check out Sky and Telescope’s handy Saturn javascript utility, free Meridian software (used to make the diagram above) or download the $2.99 app SaturnMoons.

Saturn’s the best. No other sight in the sky elicits the wonder and amazement of guests at the telescope. Look at the ringed planet every night you can, and the more friends and family your share it with, the better.

8 Responses

  1. Edward M. Boll

    I am going to be in St. Cloud this evening, not sure I will see Saturn from there. One of my favorite memories was stepping out of my former pastor’s house in the twin cities around April 9, 1997 and seeing Hale Bopp easily with just my own eyes. To me the most interesting comet of next week is Linear 209. As it gets close to earth and rapidly brightens I was hoping for a magnitude of 9 or 10 in a week, not sure that it will get that bright.

    1. astrobob

      Hi Blu,
      Yes, it will. You’ll be able to see Saturn all spring and summer long. It will gradually get higher and even easier to see in the coming weeks.

  2. Troy

    I was very lucky and was able to observe Saturn on Saturday (lowsy weather before and after). The bright rings were fabulously glowing white. Maybe because I had just been to the dentist earlier in the day it reminded me of celebrities who get too much tooth whitening.
    I’m wondering how long the Seeliger effect lasts. It must be just a couple of days because I don’t recall seeing it last year and I think I was able to see it a couple of days before opposition.

      1. Troy

        After an entire week of cloudy weather I finally got another look at Saturn. It would seem the Seeliger effect is still in effect, perhaps a bit diminished.
        I have yet to process today’s images, but it will be interesting to compare them.

        1. astrobob

          Hi Troy,
          It appeared obvious to me tonight through the 10-inch scope too. Let us know when you have side-by-side images.

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