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Sky&Telescope Article<br /><br /><font color="orange">On Thursday, August 16th, Earth will cross the equator and ring plane of Uranus, and astronomers all over the world will be on watch. The unusual geometry offers a unique view of the planet's atmosphere, satellites and ring system. "This won't happen again for a long time," says planetary researcher Heidi Hammel (Space Science Institute, Colorado). "We don't know what we're going to see. It's exciting."<br /><br />Uranus's orbital period of 84 years means that we get ring-plane crossings only every 42 years. During the last one, in 1965, little was known about the distant planet, the ring system hadn't been discovered, space telescopes sounded like science fiction, and the 5-meter Hale telescope on Palomar Mountain was the world's largest. "To study Uranus, you need big telescopes," says Hammel. "This is really the first time we can do these kind of observations."<br /><br />Because of Earth's own orbital motion, our planet actually crosses the Uranian ring plane three times in succession: on May 2, 2007, August 16, 2007, and February 20, 2008. The August event is by far the most favorable; Uranus will be less than a month from its opposition to the Sun (on September 9th), so it will be visible almost all night (in Aquarius). Another interesting fact is that December 7, 2007, is the date of Uranian equinox, when the Sun will cross the planet's equatorial plane.</font>/safety_wrapper> <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>