Gazing into the Cat’s Eyes

Soon after sunset on September 10th and 11th, the nascent crescent moon joins Venus low in the west. These two are the first two lights to appear after sunset, around 7:20 Saturday, when Venus shines six degrees to the right of the moon.

Sunday, the moon and Venus form a loose triangle with the dim star Zubenelgenubi in the constellation Libra.

Monday, the waxing crescent moon shines just a few degrees to the west of Antares, the heart of Scorpius. A summer constellation traveling along the ecliptic, Scorpius hugs the southern horizon throughout its apparition. As a result, the light from Antares cuts through a thick swath of earth’s atmosphere before reaching our eyes. Coupled with the 550 light years that its light travels before reaching us, this makes Antares one of the most twinkling stars in the heavens.

To the Chinese, Antares is Ta Who, The Great Fire, and does it ever burn. The 15th brightest star, Antares is a red supergiant 10,000 times brighter than our sun and 700 times bigger. Were it in place of the sun, it would engulf Mercury, Venus, Earth, Mars and reach two-thirds of the way to Jupiter. For all that, Antares is far cooler than the sun, burning at 6,500 degrees compared to the sun’s 11,000 degrees. And while it is large, it is not massive, with less than one-millionth the density of the sun.

Tuesday and Wednesday nights, the moon hovers above and to either side of the curved tail of Scorpius. Two stars make up the stinger — Shaula and Lesath — also known as the Cat’s Eyes. Binoculars or a small telescope reveal that these eyes are actually thousands of stars, with a distinct pattern cutting through the center like the pupil of a cat’s eye. These two stars mark the southern end of the Milky Way, which stretches north-northeast through the Summer Triangle up to and beyond Cassiopeia.