“Starting at 4:20 p.m. the shadow of the earth will begin to pass over the face of the moon,” says Kenji Shimizu, professor of astronomy. “What will be truly unique about this eclipse will be that the corona that surrounds the black disk of the darkened moon will not be the usual somewhat dim orange corona. Instead, there’s a very good chance it will be surrounded by a brilliant reddish corona.”
The eclipse will reach it’s greatest magnitude around 5:17 p.m. and will start to recede at 5:53 p.m. By 7:01 p.m. it will be fully over, you can go back to your desk and turn down the loud music.
Eclipses of the moon occur when the moon, earth and sun line up perfectly, and the shadow of the earth blocks out any light from reaching the moon. As the orbit of the moon around the earth is at a different angle of the tilt of the earth, lunar eclipses occur intermittently, but can be predicted accurately by mathematical cycles as the Soros cycle.
“Light bending through earth’s atmosphere is what gives the moon its corona during an eclipse,” says Shimizu. “But this year because of all the volcanic ash in the atmosphere, the light will be refracted, and we may get a real show.”
Much of the ash thrown into the atmosphere by the Eyjafjallajokull volcanic eruption in Iceland that severely disrupted European air traffic this year is still suspended in the atmosphere. The volcanic ash from an eruption of this scale usually floats in the earth’s atmosphere for a number of years before finally settling to earth. During this time it distorts light passing through the atmosphere.
“The eclipse can be seen from anywhere in Japan, and in fact, can be seen from the entire half of the world facing the moon at the time of the eclipse,” Shimizu noted. “Unlike a solar eclipse which usually lasts only a few minutes, a lunar eclipse lasts from beginning to end for a few hours.”
In ancient times it was believed that a gigantic turtle swallowed the moon. And used to beat on pots and pans and yell and scream until the turtle disgorged the moon. All things considered, it might be a good idea to grab a pan and start screaming and pounding on it when the moon gets really blacked out.
Photo by Dave Powell of ShootTokyo.com