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Wednesday, October 7, 2015

Earthsky Tonight, February 6, 2010 Moon and star Antares pair up before dawn

Courtesy of EarthSky
A Clear Voice for Science

If you’re an early riser, you can see the waning crescent moon next to the star Antares during the dawn and predawn hours on Sunday, February 7. Look in the south to southeast sky for this shining couple an hour or so before sunrise.

Antares is the brightest star in the constellation Scorpius the Scorpion. In our northern hemisphere, Antares is considered a summertime star, because it’s during the summer months that this star shines in the evening sky. By October, Antares has begun to move behind the sun as seen from Earth, and then it appears only briefly, low in the west after sunset each evening. By November, Antares has completely disappeared from the evening sky.

Every year, the sun and Antares are in conjunction on or near December 1. In other words, that’s when Antares is most directly behind the sun each year, as seen from our earthly vantage point. Then, the sun and Antares rise and set in unison, so that Antares is lost in the light of the sun throughout December. However, by mid to late January, Antares drifts far enough west of the sun so that it appears above the southeast horizon before sunrise. What’s really happening, of course, is that Earth – in its constant motion in orbit around the sun – has moved far enough along that this star begins to appear to one side of the sun, instead of behind it.

Seeing Antares and its constellation of the Scorpion before dawn is a sure sign that the shortest days of winter have passed. Tomorrow, we’ll tell you a Pawnee tale about the Scorpion’s tail and the return of spring.

Written by Bruce McClure

Other Links:

Sky and Telescope

National Geographic

Space Com

Amazing Space

The York County Astronomical Society

Scope City

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