June 26th--Lunar Eclipse  

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This Saturday morning, June 26th, there's going to be a lunar eclipse—and for many residents of the USA, it's going to be a big one.

The eclipse begins at 3:17 am PDT (10:17 UT) when the Moon enters the sunset-colored shadow of Earth. By 4:38 am PDT (11:38 UT), the moment of greatest eclipse, 54% of the Moon's diameter will be covered. From beginning to end, the event lasts almost three hours.

Although the eclipse is only partial, it will be magnified in size and charm by the "Moon Illusion"--a result of the eclipse occurring close to the horizon from viewing sites in the USA.

For reasons not fully understood by astronomers or psychologists, low-hanging Moons look unnaturally large when they beam through trees, buildings and other foreground objects. In fact, a low Moon is no wider than any other Moon—cameras prove it—but the human brain insists otherwise.

Who are we to argue?

The effect will be particularly strong in western and central parts of the USA and Canada where the Moon will be setting as the eclipse reaches maximum. (Observing tip: Look low and to the west just before dawn.) The fact that the extra size is just an illusion in no way detracts from the beauty.

People in New England and northeastern Canada will justmiss it. The Moon sets shortly before the eclipse begins.

Halfway around the world, observers in India, Japan, and parts of East Asia will experience the same phenomenon. They'll see the eclipse on Saturday evening as the Moon is rising. The Moon Illusion will be fully active as Earth's shadow sweeps across low-hanging lunar terrain.

It almost makes you feel sorry for people living on the dreamy islands of the South Pacific. There the eclipse takes place directly overhead, high in the midnight sky where the Moon Illusion does not work. That's okay. A partial lunar eclipse is a beautiful thing all by itself.

Credit to:

NASA Science News for June 24, 2010
Ravensgrove Coven

This entry was posted on Saturday, June 26, 2010 at Saturday, June 26, 2010 and is filed under , . You can follow any responses to this entry through the comments feed .



Actually, the effect of the moon appearing larger at the horizon (and also the sun) is due to atmospheric lensing. The air closer to earth is filled with more particles that refract light making the moon and sun appear larger than normal. This effect also is the reason for the sun and moon appearing red or orange near the horizon and also for the amazing sunset/sunrise colors. Idk who told you that astronomers do not know why that happens. I learned about that in school.

June 28, 2010 at 11:50 AM
Witchy Mama  

Thank you for the info. I will be sure to pass that along.

June 29, 2010 at 7:28 AM

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