In the Sky This Month

Antares, the heart of the scorpion, is quite near the Moon tonight. Antares is more than a dozen times the mass of the Sun and tens of thousands of times brighter. In the next million years it’s likely to explode as a supernova.

Two stars that form the scorpion’s “stinger” peek above the southern horizon on summer nights. The stars are Lambda and Upsilon Scorpii. Lambda is the brighter of the two.

U Scorpii, a star system on the far side of the galaxy, has produced 12 outbursts since 1863. The system is in Scorpius, which is low in the south-southeast at nightfall. U Scorpii is above the curving line that outlines the scorpion’s body and tail.

Spica, which represents a stalk of wheat held in the hand of Virgo, the maiden, perches close to the upper right of the Moon at nightfall. It is one of several bright stars in the night sky that are likely to end their lives with brilliant explosions.

The scorpion skitters low across the south on summer nights. Its brightest star is Antares. The scorpion’s body and tail curl to the lower left with the head to the upper right, marked by a line of three evenly spaced stars that are of roughly equal brightness.

The Moon is at first quarter today. It lines up at a right angle to the line between Earth and the Sun, so sunlight illuminates half of the lunar hemisphere that faces Earth.

Summer arrives in the United States in the wee hours of tomorrow morning at the moment of the June solstice. At the solstice, the Sun stands farthest north for the entire year. The solstice marks the longest day of the year in the northern hemisphere.

Regulus, the brightest star of the constellation Leo, stands close to the right or lower right of the Moon at nightfall. They stay close together as they drop down the western sky, and they set around midnight.

The Little Dipper extends almost straight up from the North Star, Polaris, in early evening. It is part of the constellation Ursa Minor, the little bear. The dipper spans about 20 degrees, which is the width of your spread-out hand held at arm’s length.

The crescent Moon is low in the west at sunset. And it has a prominent companion: Venus, the brilliant Evening Star. They drop from sight a couple of hours later.