In the Sky This Month

There’s a beautiful conjunction in tomorrow’s early morning sky involving the Moon, the planet Venus, and the star Regulus. They are quite low at first light. Venus is the Morning Star, with Regulus a bit farther from the Moon.

The next few evenings offer a great chance to see the Milky Way, the hazy band of light that outlines the disk of our home galaxy. It arcs high across the sky at nightfall, and there’s no Moon around to spoil the show.

Cassiopeia is a third of the way up the northeastern sky as night falls. Its stars form a letter “W.” The brightest star, Schedar, is at the lower right point of the W. It is a young star, but so massive that it’s already nearing the end of its life.

Pollux, the brightest star of Gemini, will stand close to the lower left of the Moon early tomorrow, with Jupiter to the lower right of the Moon. Jupiter, the brightest object in the night sky after the Moon and Venus, is the largest planet in the solar system.

The Moon reaches last-quarter today. It aligns at a right angle to the line from Earth to the Moon, so the Sun shines on half of the lunar hemisphere that faces our way. The Moon is waxing toward “new” on September 21.

Elnath and the Moon rise into good view after midnight, with the star to the lower left of the Moon. The Moon will slip toward Elnath, the second-brightest star of Taurus, as they climb higher. From the far-southwestern U.S., the Moon will cover the star.

Sagittarius is due south at nightfall. The constellation looks like a teapot. The center of the galaxy is in the “steam” rising from the spout. Giant clouds of dust absorb the light from the galaxy’s heart, so it takes special instruments to see anything there.

With autumn drawing close, some of the constellations associated with the season are climbing into prominence. Pegasus, the flying horse, spreads his wings across the eastern sky at nightfall, with Andromeda, the princess, to his lower left.

The Moon passes closest to Earth today for its current cycle of phases, at a distance of less than 227,000 miles, which is about 12,000 miles closer than average. Tides are higher at this point, known as perigee.

The constellation Cetus is entering the late-evening sky. Early star maps depict it as a fish with the head of a dragon or lion. Cetus had an appetite for young ladies, but when he tried to devour the princess Andromeda, he was slain by Perseus.