red supergiant

Skywatchers will be treated to a striking celestial pairing soon after sunset on Monday, July 7, as the moon passes close to one of the largest stars visible to the naked eye.

Now, just a few days from being full, the moon will be very bright and make stars hard to see in the night sky, but Antares won’t be missed. This red supergiant will shine to the upper right of the moon.

Meet The ‘Rival Of Mars’

Antares is a red supergiant star — a dying star. The 15th brightest in the night sky, it’s one of the largest stars we know of. If it was in the solar system in place of the sun, Antares would stretch all the way to between the orbits of Mars and Jupiter. According to BBC Sky At Night, Antares is 76,000 times more luminous than the sun.

Its name means the “rival to Mars,” with ant meaning anti and Ares referring to the Greek name for Mars. It gets that name not only because it’s reddish but because Mars sometimes passes close to Antares.

As the brightest star in the constellation Scorpius — a constellation best known for its curved “tail” — Antares is often called the “heart of the scorpion.”

When And Where To Look And What You’ll See

To catch this event, head outside shortly after sunset and find a clear view of the southeastern sky. The 92%-lit waxing gibbous moon will already be visible long before it gets dark, but as twilight begins, Antares will appear, glowing about four degrees above it. The moon will be around 248,145 miles (399,350 kilometers) from Earth, while Antares is about 550 light-years distant — a whopping 13 million billion times farther!

From mid-northern latitudes, only part of the Scorpion’s body rises above the southern horizon during the summer months. But even from these latitudes, the constellation’s claws — Achrab, Dschubba and Fang—should be visible above Antares.

Observing Tips

All you need for this sight is your naked eyes and a clear sky to the southeast. A stargazing app like Stellarium might help you locate the stars of Scorpius.

What’s Next In The Night Sky

If you can rise before the sun on Tuesday, July 8, you’ll see Venus shine brightly at its highest point in the morning sky during its current apparition. Although July 8 sees its highest point, it will be easy to see in the pre-dawn darkness until around July 21.

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.