In the Sky This Month

The constellation Scutum, a small, faint “shield” of stars, scoots low across the south on early-summer nights. It represents the shield of John Sobieski, a 17th-century king of Poland. You need dark skies to make it out, however.

The Moon is at last quarter today. Sunlight illuminates half of the lunar disk that faces Earth. The “last-quarter” name indicates that the Moon is three-quarters of the way through its month-long cycle of phases.

Half of the constellations of the zodiac line up across the south as night falls this evening. They stretch from Cancer, which is quite low in the west, to Leo, Virgo, Libra, Scorpius, and finally Sagittarius, which is low in the southeast.

The Milky Way is beginning its journey into summer’s evening skies. It arcs low across the east not long after nightfall. It’s anchored by teapot-shaped Sagittarius in the south, the graceful swan in the east, and W-shaped Cassiopeia in the north.

Saturn stands near the Moon the next few mornings. The Sun’s second-largest planet looks like a bright star. It will stand well to the left of the Moon at dawn tomorrow, but much closer to the Moon on Thursday.

Three planets are in view at dawn. Saturn is half way up the southeastern sky and looks like a bright golden star. Mars is due east and shines just as brightly as Saturn. Brilliant Jupiter stands to the lower left of Mars.

Altair, the brightest star of the eagle, is one of the 12 brightest stars in the night sky. But Tarazed, a fainter star that appears just above it as night falls, is actually about 200 times brighter. It looks fainter only because it’s about 35 times farther away.

A young eagle soars across the sky on June nights. Altair is low in the east at nightfall and high in the southwest at dawn. It represents the breast of the constellation known as the eagle. The name “Altair,” in fact, means “the flying eagle.”

There’s an astronomical coincidence today: It’s the first full day of summer in the northern hemisphere and there’s a full Moon. The exact moments of the two events are a bit more than one day apart, which is a coincidence that happens once every couple of decades.

Astronomically, today marks the start of summer in the northern hemisphere. It’s the summer solstice, which is the longest day of the year north of the equator. It represents a turning point for the Sun, which will begin to move southward after today.