In the Sky This Month

Capella, the brightest star of Auriga, the charioteer, stands high overhead this evening and wheels across the northwest later on. It looks yellow with a hint of orange. It is one of the half-dozen brightest star systems in the night sky.

Pollux, the brightest star of Gemini, perches quite near the Moon this evening. Its “twin,” the star Castor, is a good bit farther from the Moon. Pollux has expanded to about nine times the diameter of the Sun — a beach ball to the Sun’s golf ball.

Venus and Mars will huddle close together the next few mornings, quite low in the east-southeast during the waxing twilight.

Hydra, the water snake, spans more than 100 degrees — almost a third of the way around the sky — so it takes a long time to climb into view. Tonight, for example, its head is in the east-southeast at nightfall, but its tail won’t rise until about midnight.

The Moon slides along one of the horns of Taurus tonight. At nightfall, the bull’s eye, the star Aldebaran, is to the lower right of the Moon. The tip of the horn, El Nath, is closer to the left or lower left of the Moon.

The Pleiades star cluster, which forms the shoulder of the celestial bull, is close to the Moon tonight. Its brightest stars form a tiny dipper. It may be hard to pick out through the moonlight, but binoculars will help.

Kappa Ceti, a star that is the same class as the Sun, is in Cetus, the whale or sea monster. The star is about 30 light-years away. It’s almost exactly the same size and mass as the Sun, although slightly fainter. Like the Sun, it belongs to class “G.”

Jupiter, the largest planet in the solar system, looks like a brilliant star near the Moon tonight. After the Moon, Jupiter is by far the brightest object in the sky for most of the night.

One of the busiest stellar nurseries in the galaxy stands about half way up the southern sky at nightfall now. The Orion Nebula has given birth to thousands of stars, with many more taking shape even now.

Cassiopeia, the queen, is written large across the northern sky this evening. It looks like a big letter M or W. It’s high in the northwest at nightfall and drops low across the north later on.