MIAMI - Sky watchers throughout North America will get a triple treat tonight: a total eclipse of a harvest moon, with a bright Saturn in tow.
Most of North America won't see another total eclipse of the moon until the year 2000, and astronomers say these kinds of very public displays help reconnect a generation of children who have "lost contact with the sky."
"With the amount of electric lighting we're using, we're washing out the sky," said Bob Stencil, head of the physics department at the University of Denver. "When we illuminate the sky, we're depriving children of a chance to tap into the cosmic wellspring of creativity and imagination."
A total lunar eclipse occurs whenever the Earth moves directly between the sun and the full moon, casting its shadow across the moon. Even when the moon is completely in the Earth's shadow, it doesn't get entirely dark; it is often a faint reddish, illuminated by sunlight filtering around the Earth's edge.
This time, Earth's curved shadow will fall across the moon starting at 9:12 p.m. EDT, with the darkest part of the eclipse coming at 10:54 p.m.
This lunar eclipse comes at the same time as the harvest moon, which is the full moon closest to the first day of autumn. A harvest moon is not necessarily different from other full moons, but crisp, dry fall weather can make it seem brighter and more distinct.
Making things even more interesting this time, Saturn is positioned in the sky very close to the eclipsed moon. As the moonlight dims, stars will come out and Saturn will seem to shine more brightly.
"This is a wonderful dance between the Earth and the moon, sort of a cosmic ballet," said Jack Horkheimer, director of the Miami Planetarium and host of the PBS show Star Hustler.
Dust from volcanic eruptions or smoke from forest fires can affect the color of the eclipsed moon, which can vary from a dull gray to a coppery or muddy red color. A lunar eclipse can give scientists a reading of how much dust is in the atmosphere.
Such events usually stir public enthusiasm for stargazing.
"Anybody can see the eclipse with their own eyes," said Paul Knappenburger, president of the Adler Planetarium and Astronomy Museum in Chicago. "Just find a comfortable place and watch the moon perform."