In the Sky This Month

Virgo is the second-largest constellation. It is so big that it takes about four hours to clear the eastern horizon. Yet it contains only one bright star, blue-white Spica, which climbs into view around nightfall.

NGC 6946 is the source of a lot of fireworks. Over the last century, it’s produced more exploding stars than any other galaxy. The galaxy is high in the northeast before dawn, to the left of Deneb, the bright star at the tail of the swan.

A nebula in the constellation Vela spans about 16 times the width of the Moon in our sky – almost as big as your fist at arm’s length. The Vela Supernova Remnant is 800 light-years away. It was born 11,000 years ago, when a supergiant star exploded.

Our stellar neighborhood is thinly settled. Only 11 stars lie within 10 light-years of the solar system, and only one of them is visible from northern skies: Sirius, the brightest star in the night sky, which is in the southwest in early evening.

Auriga, the charioteer, drives across the western sky this evening. Its brightest star is yellow-orange Capella, which stands high in the west-northwest as darkness falls.

Polaris, the North Star, marks the north celestial pole. But it is not especially bright, so it can be tough to find. The Big Dipper serves as a pointer. The two stars that mark the outer edge of its bowl point almost directly toward Polaris.

Mars remains in good view in the early morning. It forms the lower left end of a lineup of three planets at first light. Saturn is to the upper right of orange Mars, with brilliant Jupiter farther along the same line.

A brilliant point of light in the evening sky is sweeping past one that’s merely bright. The brilliant light is Venus, the “evening star.” The merely bright light is Aldebaran, the eye of the bull, to the left of Venus and a little higher in the sky.

Canes Venatici, the hunting dogs, is awash in beautiful galaxies. The constellation is in the east-northeast as night falls, to the right and lower right of the Big Dipper. Four of its prominent galaxies are visible through small telescopes.

Regulus, the bright heart of Leo, the lion, shines close to the right or upper right of the Moon as night falls this evening. It will be to the lower right of the Moon as they set, a couple of hours before sunrise.