Wednesday, April 11, 2012

The Rings of Saturn Will Be On Display This Weekend

Time to pull out your telescopes and binoculars folks.

On April 15, Saturn reaches opposition — the point when it is directly opposite the sun in the sky. When it reaches opposition, Saturn will appear in the midnight sky to observers on Earth. The sky maps and illustration of Saturn accompanying this guide shows where to see the planet in the southern sky on April 15 and how it may appear seen through a good telescope.

The most important thing about this for skywatchers is that Saturn moves from being a "morning object" to being visible all night. For all of April, Saturn rises at sunset, and sets at sunrise.

All the outer planets have rings, but with the exception of Saturn, they are only visible in long exposure photographs made from space. Saturn's rings are totally in your face, as bright as the planet itself. They are made up of many thousands of small pieces of rock and ice, with enough space in between for starlight to shine through. [ Photos: Spectacular Views of Saturn's Rings ]

From a distance they look substantial and solid, yet in reality they are gossamer thin: thousands of kilometers wide, yet only a few kilometers thick. Through a good telescope, the rings are seen to have a complex structure.

Here’s a list of the brightest moons and their brightness on April 15, the night of Saturn's opposition:

  • Titan: 8.4
  • Rhea: 9.7
  • Tethys: 10.2
  • Dione: 10.4
  • Iapetus: 11.1
  • Enceladus: 11.7

Astronomers use an upside down magnitude scale: the larger the number, the fainter the object. At magnitude 8.4, Titan is easily visible in binoculars. One of the two largest moons in the solar system, it is the only moon with a substantial atmosphere, mostly methane gas. It was visited by the Huygens lander on Jan. 14, 2005. [ Amazing Photos: Titan, Saturn's Largest Moon ]

With so many moons visible in a telescope, how do you tell which is which? The easiest way is to run a planetarium program on your computer: it will plot accurately the positions of all of Saturn’s moons as they circle the planet, neatly labeled for you.

This article (edited for length) was originally provided to by Starry Night Education, the leader in space science curriculum solutions.

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