UNITED KINGDOM – SEPTEMBER 11: First Quarter moon of April 11, 2011 at 21:37 hours. (Photo by Jamie Cooper/SSPL/Getty Images)
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On the evening of Sunday, Aug. 3, skywatchers will be treated to a close encounter between two of the sky’s brightest nighttime objects. Just after sunset, the waxing crescent moon will appear directly beneath the red supergiant star Antares, the brightest star in the constellation Scorpius. This striking pairing, part of a repeating cycle, will be easy to spot with the naked eye.
Where And When To Look
Look to the southwest after sunset on Aug. 3, and as twilight deepens, you’ll see the moon glowing brightly, with Antares positioned just above it. The two will be close — less than a few degrees apart — and will sink slowly toward the horizon over the next couple of hours.
What You’ll See
The pairing of Antares and a 72%-lit waxing gibbous moon will be visible from most of the world, but a clear, unobstructed view of the southwestern sky will enhance your chances of catching them before they set.
Antares means means “rival to Mars” due to its red-orange tint and the fact that Mars passes it in the night sky every few years, causing confusion. It’s a massive supergiant star located about 550 light-years from Earth and shines at magnitude 1.1.
The closeness of Antares and the moon is no fluke. The moon regularly passes close to a set of bright stars that lie along the ecliptic — the same path it follows across the sky each month — those stars being Antares (in Scorpius), Aldebaran (in Taurus), Regulus (in Leo), and Spica (in Virgo).
Sunday, August 3: Moon And Antares
Stellarium
Observing Tips
Most people immediately think of a telescope when they think about astronomy. It’s not necessary for this event. You’ll see much more just by using your naked eyes. However, a pair of binoculars is always useful when stargazing, allowing you not only to zoom in — particularly on the lunar surface — but also to better see the color of stars, such as Antares. It will look red, though since it’s so low, its light may be distorted by Earth’s atmosphere, so could flash a variety of colors, such as yellow and white.
Choose an observing location with a clear, unobstructed view to the eastern horizon, if possible, away from city lights — though light pollution makes zero difference when observing the planets, the moon and particularly bright stars.
What’s Next In The Night Sky
August is perfect for finding Vega, the brilliant anchor of the Summer Triangle, high in the southeast after dark. Also coming up is the full sturgeon moon on Aug. 9 and the Perseid meteor shower peak — though hampered by moonlight — on the nights of Aug. 12-13. The best nights for “shooting stars” could actually come later, around Aug. 15. There’s also a close conjunction of Jupiter and Venus on Aug. 12.
For exact timings, use a sunrise and sunset calculator for where you are, Stellarium Web for a sky chart and Night Sky Tonight: Visible Planets at Your Location for positions and rise/set times for planets.
Wishing you clear skies and wide eyes.