A Guide to the Winter Constellations — Orion and the Jewels of the Night Sky
At the heart of the most brilliant sky of the year — winter — stands Orion. Using Orion as your reference, trace the Winter Triangle and the Winter Hexagon, and enjoy the Orion Nebula and the Pleiades with the naked eye on this journey through the winter sky.
The king of the winter sky — Orion
The first thing to catch your eye in the winter night sky, and the easiest, is Orion. Around 9 p.m. from December to February it rises boldly from the southeast into the southern sky, with three bright stars in a row at its center (the Belt) marking the hunter's waist, and red Betelgeuse and blue Rigel shining diagonally opposite above and below. The color difference between these two is obvious even to the naked eye — a fine example of a star's temperature revealed through its color.
The three Belt stars are the all-purpose compass of the winter sky. Extend them down to the lower left and you reach Sirius (in Canis Major), the brightest star in the night sky; extend them up to the upper right and you pass Aldebaran, the red eye of the bull (in Taurus), and arrive at the Pleiades cluster. Find Orion, and you can star-hop across the whole winter sky.
The Winter Triangle and the Winter Hexagon
Starting from Betelgeuse in Orion and joining Sirius in Canis Major and Procyon in Canis Minor completes the "Winter Triangle," close to a large equilateral triangle. All three stars are so bright that they show clearly even in the city, making the surest reference for getting your bearings in the winter sky.
Widen your view further and the "Winter Hexagon (the Winter Diamond)" emerges. Beginning at Sirius and joining Procyon, then Pollux in Gemini, Capella in Auriga, Aldebaran in Taurus, and Rigel in Orion in turn, you draw a giant hexagon spanning half the sky, with red Betelgeuse set right at its center. With all six vertices shining at magnitude 0 to 1, this ring of stars shows the winter sky — when the most bright stars of the year gather — at its most spectacular.
Jewels of the winter sky — the Orion Nebula and the Pleiades
Below Orion's Belt, three small stars hang like a "sword," and the middle one looks faintly blurred. This is the "Orion Nebula (M42)," which you can make out even with the naked eye. About 1,300 light-years away, this vast cloud of gas is a cradle of the cosmos where new stars are being born at this very moment — with binoculars you see the wings of nebulosity spreading hazily, and with a telescope, the four newborn young stars within it (the Trapezium) are revealed.
From Orion, pass Aldebaran and rise a little higher, and a small knot of stars packed tightly into a narrow space catches the eye. This is the "Pleiades cluster (M45)" in Taurus. Usually six or seven stars show to the naked eye, earning it the name "Seven Sisters," and with binoculars dozens of blue stars open up in a dazzling scatter of jewels. Our ancestors gauged the seasons and farming times by this cluster's position in the early evening.
The hunter and the scorpion — the myth of Orion
Orion is a giant hunter of Greek myth. He is said to have boasted too much of his hunting prowess and to have died from the sting of a small scorpion — which is why, in the sky, Orion and Scorpius flee each other and never share the sky at the same time. When Orion rises into the winter sky, the summer scorpion hides below the horizon; when the scorpion rises in summer, Orion withdraws.
At Orion's feet follow two faithful hunting dogs, Canis Major and Canis Minor, while before him the fierce bull Taurus lowers its horns. The winter sky thus unfolds like a single hunting scene of the hunter, his dogs, and the bull — and there is a special delight in star-hopping among the bright stars as if pointing out the cast of a myth.
Best times and directions to observe
The winter constellations climb high from the southeast into the southern sky between 8 and 11 p.m. from December through February, when observing conditions are at their best. Around 10 p.m. in January, Orion hangs due south and the Winter Triangle and Winter Hexagon fill half the sky, offering the brightest, most spectacular sky of the year.
Winter air is dry and cold, so stars appear especially sharp and sparkling. The cold, however, is the greatest enemy of observing, so bundle up firmly in thick winter clothing, gloves, and hand warmers. Chilled hands and feet will cut your session short, so the warmer you come prepared, the longer and more comfortably you can enjoy the jewels of the winter sky.