Earthsky Tonight
Give me five minutes, I’ll give you Saturn in 2010
03-01-2010 - Astronomy Essentials
I want you to see Saturn at its best in March and April 2010.
Earth goes around the sun once a year. Saturn goes around the sun once about every 30 years. So you can see that our planet Earth has to pass between Saturn and the sun every year. In 2009, that happened on March 8. In 2010, this event – called an opposition of Saturn – will happen on March 21 according to U.S. clocks.
That makes March and April of 2010 the best months for seeing this most amazing and beautiful of planets. Will you be ready? Save this article!
Can you see the rings of Saturn if you look with the eye alone? No. But you can see this golden world with your unaided eye. It will appear as a bright golden “star” … very beautiful. And unlike the twinkling stars, Saturn will shine with a steady light. That might help you identify it.
Since Saturn moves only slowly with respect to the true stars, once you notice the starry pattern around Saturn this year, you can spot this planet for several months at its best.
Okay. How can you see Saturn?
First, think about the fact that – when Earth goes between the sun and Saturn – Saturn appears opposite the sun in our sky. That means that, if you’re looking for Saturn during the evening hours around the time of its 2010 opposition (March 21), you should be facing east, with your back to the sunset direction, in order to see Saturn.
In late March and early April, 2010, go outside after night falls and stand facing east. If the sun has just gone down, Saturn will be on the horizon, probably too low in the sky to see. So wait until mid-evening, when it’s good and dark, and Saturn is higher in the sky. Then you’ll have a better chance of spotting it.
Think of it this way. As the sun sinks below the western horizon, Saturn will rise above the eastern horizon at a similar rate. Why? Because, remember, at opposition, Saturn is opposite the sun!
What makes it possible to pick Saturn out from the multitude of glittering stars?
The answer is that Saturn will be bright. In fact, every year around the time we go between the sun and Saturn, the ringed planet is at its closest to Earth and brightest in our sky. Then it appears about as bright as the brightest stars. As our chart shows, Saturn will make a triangle in 2010 with two bright stars, Arcturus and Spica. These are famous stars – and easy to spot – in a way we’ll explain shortly.
Arcturus will be the only star near Saturn that appears significantly brighter than the ringed planet. Arcturus is the 4th brightest star in all the heavens. It’ll be to the north (left) of Saturn on late March and April evenings. How do you know which one is Arcturus? There’s an old saying, used by scouts and stargazers: “Follow the arc to Arcturus.” Just follow the curve in the handle of the Big Dipper to be sure you’ve spotted this star. Here’s a chart showing show to do it.
How about Spica? How can you tell Saturn from Spica. It so happens you can use the Big Dipper here as well. Scouts and stargazers say: “Follow the arc to Arcturus and speed on to Spica.” In other words, if you’ll extend the curve in the Big Dipper’s handle past Arcturus, you’ll come to Spica. This chart will show you how.
See Arcturus and Spica then? Saturn makes a triangle with these two stars on spring 2010 evenings. So if you are outside in the evening – looking in the direction opposite the sunset – you can’t miss seeing it.
Once you start looking carefully, you might even notice that Arcturus and Spica are twinkling, while Saturn is shining more steadily. You know the old folk wisdom about stars twinkling and planets shining with a steady light? It’s true.
How can you see Saturn after late March of 2010?
After March 21 – when Earth goes between Saturn and the sun – Earth will be fleeing ahead of Saturn in the race of the planets around the sun. What does that mean? For one thing, Saturn will begin appearing fainter throughout April than it was in March because the distance between our two worlds will be increasing.
Also, Earth’s motion in orbit will means that – when the sun sets – Saturn will already be above the horizon. So this planet will be very prominent in April of 2010, shining in the east as soon as the sun goes down. Every evening, as Earth continues moving on in orbit around the sun, Saturn will appear higher in the east at sunset after March of 2010.
Saturn will remain somewhere in our sky – as it always does – for most of this year. But the planet will be fading in brightness after March. So it will become less noticeable. As Earth moves in orbit, we’ll see Saturn shift its location in our sky. Each night at sunset, it will appear to be farther to the west. Finally, in September of 2010, Saturn will disappear in the western twilight after sunset.
In late October, Saturn will reappear in the east before dawn. It’ll start its cycle anew, rising earlier each day, until the next time Earth passes between Saturn and the sun in the year 2011.
By the way, this event – our passing between the sun and Saturn, bringing this world to opposition in our sky – happens about two weeks later with each passing year. The 2008 opposition was on February 24. The 2009 opposition was on March 8. The 2010 opposition is on March 21. And the 2011 opposition will be … you guessed it … on April 3.
One last thing, for you telescope users, from February 11, 1996 to September 4, 2009, the south side of Saturn’s rings were facing in Earth’s direction. Since then, we’ve been looking at the north side of Saturn’s rings. Enjoy!
There amystery theories about the planets but all inal every planet revolves around the star and it seems there are many planets in the sky to be discovered.
Last time Iread the article published by NASA that there ahuge planet coming to hit the planet earth by 2012 but if that is true that every olanet has torevolve around the star what about that huge planet coming from no where ti come & hit planet earth.Any one whone better can help me.Thank you.
Karega, thank you for your note. There is no huge planet coming to hit Earth in 2012. I’m sure you didn’t read that from NASA. It’s just not true.
Best,
Deborah
Thank you very much for the article. It is so clear, even for a beginner like me. Tonight I am looking for Saturn. I would like to see his rings, but I guess my 10*50 binoculars won\’t do.