1:45pm

Fri December 9, 2011
The Two-Way

Total Lunar Eclipse On Saturday, Western States Get Rare View

The last total lunar eclipse of 2011 — and the last one until April 15, 2014 — occurs Saturday morning.

And though those of us in the eastern U.S. won't really be able to enjoy it, NASA says that some folks in western states will have "a rare way to begin the day." If the sky is clear, they'll be able to "face west to see the red [eclipsed] moon sinking into the horizon" as the sun rises behind their backs to the east.

The best part of the show should be between 6:06 a.m. and 6:57 a.m. Pacific time.

The Washington Post's Capital Weather Gang blog notes that it might not seem possible for anyone to be able to see a rising sun and a fully eclipsed moon at the same time because "by definition, a lunar eclipse occurs when the sun and moon are 180 degrees apart, with Earth moving between them to form a straight line."

But, thanks to atmospheric refraction, the rare view will be available if you're in the right place.

As Space.com explains:

"Atmospheric refraction causes astronomical objects to appear higher in the sky than they are in reality. For example: when you see the sun sitting on the horizon, it is not there really. It's actually below the edge of the horizon, but our atmosphere acts like a lens and bends the sun's image just above the horizon, allowing us to see it. ...

"The same holds true with the moon, as well."

There's even a name for when an eclipsed moon sets just as the sun rises: it's a selenelion (or selenehelion, Space.com says).

Among cities where Space.com says the effect should be visible, assuming the skies are clear: Los Angeles, Phoenix, Denver and Winnipeg. It has a chart showing some cities and their selenelion times posted here.

Other good views of the eclipse (though not a rising sun at the same time), says ABC News, will be "from places like Hawaii, Alaska and Guam, where it will be the middle of the night, and from eastern Asia and Australia, where (remember, they're on the other side of the International Date Line) it will be Saturday evening."

Regular Two-Way readers know we do enjoy a lunar eclipse.

Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.