In the Sky This Month

Spica, the leading light of the constellation Virgo, will stand to the upper right of the planet Mars at dawn tomorrow. Spica is the brighter of the two, while Mars shows a distinctly orange tint.

The Moon is low in the east early this evening, with Aldebaran to its lower left. The star will stand above the Moon at first light tomorrow. By then, the planet Mars and the star Spica will stand side by side in the southeast, with Mars on the left.

Lyra is in the west as night falls, marked by its brightest star, Vega. RR Lyrae, a star that plays a key role in measuring the distances to all stars, stands above Vega. You need binoculars or a telescope to spot it, however.

Cassiopeia the queen is one of the most prominent star patterns of autumn and early winter. The W- or M-shaped constellation circles the North Star like the hand of a clock, though in a counter-clockwise direction.

Myriad bright stars twinkle across the sky early this evening. In the west, look for the stars of the Summer Triangle, Vega, Deneb, and Altair. Fomalhaut is low in the south, and yellow-orange Capella is low in the northeast.

The constellation Pisces passes across the south this evening. It consists of two delicate streamers of stars that join to form a V. The point of the V is sometimes called the Heavenly Knot. Star lore says it ties two fish together by their tails.

Orion climbs into view in the east by 8 or 9 p.m. Look for its belt, which is a short line of three bright stars standing almost straight up from the horizon, with a bright orange star to its left and a blue-white star to the right.

The Moon reaches its first-quarter phase at 11:03 a.m. CST today, so sunlight will illuminate half of the hemisphere that faces Earth. The “first-quarter” name indicates that the Moon is one quarter of the way through its month-long cycle of phases.

Capella, the brightest star of Auriga, the charioteer, is low in the northeast at nightfall. The yellow star arcs high overhead after midnight and is in the northwest at first light. It consists of two stars that are gravitationally bound together.

Fall and winter are the best times for viewing the shimmering curtains of light known as aurorae or northern lights. They form when charged particles from the Sun strike atoms of nitrogen and oxygen far above the surface, causing them to glow.