The moon and the Scorpion July 19 to 21

The moon and the Scorpion: Star chart showing the moon traveling in front of Libra, Scorpius and Sagittarius from July 19 to 21.
In 2021, the waxing gibbous moon will be closest to Antares on July 19. But the moon moves continually eastward in orbit around Earth. And so, each night, you’ll see the moon further to the east of Antares. It’ll be edging up on the Teapot asterism in Sagittarius by July 21.

The moon and the Scorpion

The constellation Scorpius the Scorpion is at its best on July evenings. The moon will be sweeping through it early this week, July 19, 20 and 21, 2021. It’ll be closest to bright red Antares, the Heart of the Scorpion, on July 19. Watch for the moon! Despite its glare, Antares’ red color might be noticeable.

If you’re in the city – with no dark sky – you might not see the entire constellation. But you’ll see Antares near the moon. And, depending on your sky’s darkness and your latitude, you might also catch a glimpse of the Scorpion’s curved Tail. Antares and the Scorpion’s Tail are seen relatively low in the sky from latitudes like those in the northern U.S. or Canada. And so you might also notice that Antares is a fierce twinkler. Watch for its red color and propensity to twinkle wildly, especially after full moon on July 23-24.

More to see

As the moon moves away from Antares, by about July 21, you’ll see it edging near in the sky to the Teapot asterism in the constellation Sagittarius the Archer. The Teapot points the way to the center of our Milky Way galaxy.

Read more: The Teapot guides you to the galactic center.

Star chart with stars and connecting lines making up constellation Scorpius.
Scorpius is one of the few constellations that looks like its namesake. The bright red star Antares marks the Scorpion’s Heart. Notice also the 2 stars at the tip of the Scorpion’s Tail. These 2 stars – Shaula and Lesath – are known as the Stinger.

Scorpius has a J shape

Once the moon has left the evening sky and you have darkness, you can easily see the graceful shape of Antares’ constellation Scorpius. The constellation is shaped like the letter J. From the Northern Hemisphere, the bottom half of Scorpius – the curved part of the J – is close to the southern horizon when Scorpius is at its highest in the sky, as it is on July evenings.

The farther south you go on Earth’s surface, the higher the arc Scorpius makes across your southern sky. From the Southern Hemisphere, the graceful shape of Scorpius is easiest to see, arcing closer to overhead. Some cultures at southerly latitudes on Earth – used to seeing Scorpius in its entirety – see and speak of this constellation as a fishhook. For example, in Hawaii, Scorpius is known as Maui’s Fishhook.

Read more: Scorpius? Here’s your constellation

Read more: Ruby red Antares is the Scorpion’s Heart

Read more: Meet the Scorpion’s Stinger stars, Shaula and Lesath

A map of the stars in Scorpius, including Shaula and Lesath.
A map of Scorpius showing the location of the Stinger stars, Shaula and Lesath, at the tip of the scorpion’s Tail. Image via IAU /Sky & Telescope /Wikimedia Commons.

Bottom line: From anywhere on Earth, under a dark sky, you can recognize the constellation Scorpius the Scorpion and its bright red star Antares. Let the moon point Antares out to you on July 19, 20 and 21, 2021. And then you can recognize it afterwards by Scorpius’ distinctive shape.

July 19, 2021

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Deborah Byrd

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