In the Sky This Month

The M52 star cluster, which was discovered 250 years ago today, is well up in the northeast at nightfall. It’s above the sideways letter W formed by some of the brighter stars of Cassiopeia. The cluster is an easy target for binoculars.

Spica, the brightest star of the constellation Virgo, stands quite close to the Moon as darkness falls. The planet Venus, the brilliant Evening Star, is well to their lower right and sets quite early.

Vega, one of the brightest stars in the night sky, passes high overhead on September evenings. From the middle latitudes of the United States, in fact, it passes directly overhead, the point in the sky called the zenith.

Venus and the Moon, the two brightest objects in the night sky, barely peek into view in the evening twilight tonight. Venus is the brilliant Evening Star. Both bodies set well before it gets dark.

The star Gamma Cephei forms the peak of the northern constellation Cepheus, the king. The constellation looks like a child’s drawing of a house, with Gamma Cephei at the point of the roof. The system consists of two stars and at least one planet.

Arcturus, a bright yellow-orange star, is in the west this evening. To make sure you have the right star, look for the Big Dipper, in the northwest. Follow the curve of its handle away from the bowl until you reach the first bright star, which is Arcturus.

Two paths intersect on the eastern and western horizons at nightfall now: the ecliptic and the celestial equator. The ecliptic marks the Sun’s path across the sky. The equator is the projection of Earth’s equator, dividing the sky into northern and southern halves.

The planet Mercury is creeping into the dawn sky. It looks like a fairly bright star, but it’s so low that you need a clear horizon to spot it. Mercury will be a bit easier to see tomorrow because it will perch close to the crescent Moon.

The Beehive star cluster buzzes to the right or upper right of the Moon before and during dawn tomorrow. Under dark skies, the cluster looks like a hazy patch of light. Binoculars will bring it into sharper view.

The stars that represent the twins of Gemini appear near the Moon early tomorrow. Pollux, the brighter twin, stands above the Moon at first light, with Castor a little farther to the upper left of the Moon.