Exploring the winter sky
Winter finds the Big Dipper climbing the northeastern sky, with the three stars of its handle pointing toward the horizon and the four stars of its bowl standing highest. The entire sky rotates around a point near Polaris, a 2nd-magnitude star found by extending a line from the uppermost pair of stars in the bowl across the sky to the left of the Dipper. Polaris also performs two other valuable functions: The altitude of the star above the horizon equals your latitude north of the equator, and dropping a straight line from the star to the horizon points due north.
Turn around with your back to the Dipper and you'll be facing the diamond-studded winter sky. The second great signpost in the sky,
Orion the Hunter, is central to the brilliant scene. Three closely spaced, 2nd-magnitude stars form a straight line that represents the unmistakable belt of
Orion. Extending the imaginary line joining these stars to the upper right leads to Taurus the Bull and its orangish 1st-magnitude star, Aldebaran. Reverse the direction of your gaze to the belt's lower left and you cannot miss Sirius the Dog Star — brightest in all the heavens at magnitude -1.5.
Now move perpendicular to the belt from its westernmost star, Mintaka, and find the red supergiant star Betelgeuse at the upper left of
Orion. Nearly a thousand times the Sun's diameter, Betelgeuse marks one shoulder of
Orion. Continuing this line brings you to a pair of bright stars, Castor and Pollux. Two lines of fainter stars extend from this pair back toward
Orion — these represent Gemini the Twins. At the northeastern corner of this constellation lies the beautiful open star cluster M35. Head south of the belt instead and your gaze will fall on the blue supergiant star Rigel,
Orion's other luminary.
Above
Orion, and nearly overhead on winter evenings, is brilliant Capella in Auriga the Charioteer. Extending a line through the shoulders of
Orion to the east leads you to Procyon in Canis Minor the Little Dog. Once you have these principal stars mastered, using the chart to discover the fainter constellations will be a lot easier. Take your time, and enjoy the journey. Before leaving
Orion, however, aim your binoculars at the line of stars below the belt. The fuzzy "star" in the middle is actually the glorious
Orion Nebula (M42), a stellar nursery illuminated by bright, newly formed stars.
Winter constellation audio tours