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Saturday, September 20, 2014

Sky Tonight—March 23, Moon near red star Antares before dawn

Courtesy of EarthSky
A Clear Voice for Science

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phase23 Sky Tonight—March 23, Moon near red star Antares before dawnmar231 Sky Tonight—March 23, Moon near red star Antares before dawnIf you are an early riser, look out a south-facing window before dawn on March 24, 2011 – Thursday morning – to see a lovely waning gibbous moon in front of the constellation Scorpius the Scorpion.

Understanding moon phases

The reddish star near the moon is Antares, considered the Scorpion’s ruby heart. Antares is a red supergiant star, located roughly opposite in the sky from another famous red supergiant star, Betelgeuse in the constellation Orion the Hunter. Both Antares and Betelgeuse can clearly be seen as reddish stars, but not in the same sky. As a rule of thumb, when you see Antares in the sky, you will not see Betelgeuse, because it will be below the horizon. Why? Simply because these two stars are located on opposite sides of the sky dome, and thus they never appear at the same time.

Antares, the Scorpion’s heart

Betelgeuse, another red supergiant

Both stars are interesting because they are near the end of their lifetimes. Massive supergiant red stars are expected to explode as supernovae. The supernova could happen tomorrow, or millions of years in the future. Astronomers don’t really know for sure. These stars are far enough from us (hundreds of light-years) that the deadly radiation probably will not harm Earth.

How far is a light-year?

That is tomorrow before dawn: the moon and the red supergiant star Antares in your southern sky.

The westward shift of Orion, and all the stars

by Larry Sessions

 
Astronomy Picture of the Day from NASA/JPL

EarthSky: Space

CHANDRA Photo Album

U.S. Naval Observator Astronomical Information center

Universe Today

StarDate Online

Sky and Telescope

National Geographic

Space Com

Simostronomy Blog

Amazing Space

The York County Astronomical Society

Scope City

James S McDonnell Planetarium

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