Courtesy of EarthSky
A Clear Voice for Science
The moon reaches its full phase tonight, but it rides low above the horizon for mid-northern latitudes. If your southeastern horizon is rather cluttered, you might have to wait 90 minutes after sunset for the brilliant orb to clear any obstacles.
Once you have the moon well in sight, look about three lunar diameters (1.5 degrees) below it for a bright star. Tonight the moon pays a visit to Antares, the ruddy heart of the constellation Scorpius, the Scorpion. The star’s reddish character may be hard to discern next to the spotlight of the full moon. Antares may also be twinkling madly and shifting colors. When a star lies low in the sky, we see it through much more air than an overhead star. This increases the chances that atmospheric turbulence will distort incoming starlight.
Antares is a supergiant star and appears red because its outer layers are cool – at least cooler compared to other stars. Although it appears as a mere pinpoint of light in our night sky, Antares is so large that if it were to take the place of our sun, it would extend beyond the orbit of Mars.
Written by Stuart Goldman
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