NASA
NASA's Cassini mission has captured many views of the ringed gas giant Saturn -- you can too with a modest-sized telescope.
By Mark Thompson
Discovery News
We have enjoyed some incredible views of Jupiter over the last few months, and many people have been amazed at the giant planet's detail that can be seen through a modest telescope.
Well, now it's time to turn your sights to the second-largest planet in the solar system: Saturn. It is most famous for its incredibly beautiful ring system, but there is plenty more to see if you know what to look for.
A good place to start is to know where to look! Saturn rises in the east about 2.5 hours after sunset at the start of April but rises just before sunrise by the end of the month.
It's quite easy to spot, too -- it can be seen to the southeast of the bright star Spica in Virgo by around 15 degrees (just over the width of your fist held at arm's length). Along with Spica, it forms a triangle to the north east with Arcturus, the bright orange star in the constellation of Bootes.
Analysis: Hidden moons lurk in Saturn's rings
Once you have found Saturn you will notice that it has a distinctly pale yellow color, which is due to the presence of high quantities of ammonia in its atmosphere. A magnification of at least 20x is needed to be able to show the rings distinctly, so even a bird-watching telescope should give great views.
The ring system of Saturn is not unique in our solar system since Jupiter, Uranus and Neptune all have them. All planetary ring systems are made up from countless trillions of pieces of dust, ice and rock in orbit around the planet.
By increasing your telescope's magnification, and assuming the sky conditions are good, you can pick out gaps in the rings like the famous Cassini Division discovered by Jean-Domenique Cassini in 1675. The gaps in the rings are plentiful although only a few are visible from Earth, but are all the result of the presence of small moons keeping the gaps free from ring debris.
Cassini's Christmas gift: In the shadow of Saturn
Along with the lumps of rock in the rings, Saturn has some 60 moons in orbit around it and, depending on your telescope, six are within the range of amateur instruments.
By far the easiest to spot is the largest moon Titan shining at magnitude 8 but Rhea, Tethys and Dione are all worthy targets for small telescopes.
Owners of large telescopes might also be able to spot Iapetus, Enceladus and theoretically Mimas and Hyperion might just be possible. I think I did once glimpse Mimas but it was through a large telescope in exceptional conditions, but frankly I couldn't be too sure.
Color filters can really enhance the view you have of the planets and in the case of Saturn, you can use violet filters to bring out a little more detail in the ring system and orange or red to enhance features in the atmosphere.
Before you start observing make sure that your telescope has cooled down properly and that there is no dew forming on your optics. Different telescopes suffer from this in different ways so have a cheap hairdryer handy to blow air onto them to remove the dew. Wait for the rare nights that are clear and really still to get the best views of the planets; often I find the hours after midnight are by far the best as the air has cooled and the atmosphere settled down a little.
If you can stay up until the small hours you can get some stunning still skies that are ideal for hunting down fine planetary detail. Good luck!
Copyright?2013 Discovery Channel
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