Two-year lunar eclipse tetrad


By Joshua Ostrer

On April 15, there will be a blood moon overhead.

A blood moon, or a total lunar eclipse, is set to take place above the Capital Region’s heads on Monday morning at 3 a.m.

Total lunar eclipses are rare. This is the first global total lunar eclipse since Dec. 10, 2011.

However, unlike solar eclipses that are only visible from a small geographic region, lunar eclipses are visible from over 75 percent of the globe.

This particular eclipse will be visible in its entirety to almost all of the Western Hemisphere.

Additionally, it is not harmful to stare at the moon during a lunar eclipse, in contrast to the dangers present when observing a solar eclipse with unprotected eyes.

A total lunar eclipse occurs when the moon passes directly behind the Earth, passing fully into the Earth’s umbra (Earth’s shadow).

If someone where standing on the moon during the eclipse looking at Earth, that individual would be looking at the sunrise occuring around the world.

The moon passing behind the earth is actually what prompted the term “blood moon.”

As a result of the sun’s light being refracted by Earth’s atmosphere onto the surface of the moon, the moon adopts a bloody red and brown hue for the duration of the eclipse.

A total lunar eclipse doesn’t last for that long. Lunar eclipses last for roughly three-and-a-half hours.

For any observer located in the Eastern Time Zone, the first noticeable change in the moon will begin at 1:58 a.m. and end at 5:33 a.m.

However, the total eclipse won’t last nearly that long. It will appear from only 3:07 a.m. until 4:25 a.m.

This eclipse is actually the first in a set of four total lunar eclipses, called a tetrad, that are set to occur during 2014 and 2015.

Appearing in roughly six month intervals, all four will be visible at least in part by observers in the United States.

“The most unique thing about the 2014-2015 tetrad is that all of them are visible for all or parts of the U.S.,” said NASA eclipse expert Fred Espenak in a NASA Science News Update.

If you’re interested in witnessing the lunar eclipse, take a look outside early Monday morning. For more information on the eclipse, visit



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