Saturn 'Looses' it's Ring
Saturn is most popular for its majestic rings (The Lord of the Rings). In 2009, the International Year of Astronomy, Saturn's ring will vanish.


The sequence shows the tilt angle of Saturn's ring from 2008 thru 2017. In August 2009 the ring will close, i.e. be edge-on, in that it can't be seen because the ring itself is extremely thin and quite far away. What a fantastic view in 2017 when the tilt will reach its maximum!
Generated with StellarNavigator 8, AstroArts


Chinen, Okinawa, May 31th, 2009
Saturn imaged by the Cassini spacecraft. Courtesy NASA/JPL


No worries, it won't disappear physically, just apparently. While the ring system measures 282,000 km in diameter, its thickness hardly exceeds 1000 meters. When the rings are edge-on, they can't be seen from such a huge distance, even not in larger amateur telescopes. In a 1-meter-wide scale model of Saturn, the rings would be 10,000 times thinner than a razor blade.

As seen from Earth, Saturn's inclination changes over its 29.5 years orbital period. During one period, Saturn's rings appear to vanish twice, namely approximately every 15 years. This phenomena, called "ring plane crossing", occurs next between August 11 and September 4, 2009 when the tilt of the rings are precisely edge-on and therefore 'invisible'. Until August 11 we are viewing the rings from the south, or the lower plane if you will. After September 4 the view is from the north. During the following years, the ring will tilt further until it will reach a maximum opening in 2017 facing its upper side, or northern plane, towards observers on Earth.

Also noteworthy, Saturn's brightness changes much with the tilt of its rings which are quite capable of reflecting light. While edge-on, Saturn will be at its darkest - yet still visible to the unaided eye.

Many cornerstone projects are planned for the IYA 2009. Among others, low-cost telescope kits, such as the Galileoscope are presented and advertised as ideal for observing Saturn's rings. Well, for part of this year Saturn will look more like Jupiter. Through October 2009, Saturn can be found south of the constellation Leo before it enters Virgo. From August to November 2009, the planet's proximity to the Sun will prohibit night time observations.