As twilight deepens these January evenings the most celebrated constellation of the winter sky, Orion the Hunter, stretches out along the east-southeast horizon. The impression is of a resting giant, from his radiant red shoulder star, Betelgeuse, to his foot star, luminous bluish-white Rigel, with three dimmer stacked stars midway between. The three form a motif known as the Belt asterism, a star pattern that is not an official constellation. From top to bottom, the Belt stars are Mintaka, Alnilam and Alnitak. Orion travels a southerly arc in the heavens most of the night and begins to set in the west at about 3am.
Tonight, the 9th, the gibbous (greater than half) moon shines above Betelgeuse and also draws our attention to Aldebaran, the brightest light in the constellation Taurus the Bull. See Aldebaran, the Bull’s orange eye, close above Luna at a corner of the triangular head of the Bull. Aldebaran, Betelgeuse and Rigel form a right triangle. Begin to look about an hour to an hour and a half after sunset, depending on your view to the east-southeast horizon. Sundown is at 4:46pm today and a minute or two later every day.
Diagram courtesy of EarthSky.org
Notice the waxing (increasing in size) moon climb above the cityscape in the east-northeast in the late afternoon from the 9th through the 11th, visible by about 4:30pm. The Full Wolf Moon rises at 5:25pm on the 12th, followed 20 minutes later, to the moon’s lower right, by Procyon, a distinctly yellowish-white star. Procyon is the brightest star in the Little Dog (Canis Minor) and the only star in the constellation remarkable to naked eye stargazers. Trace a straight line from Procyon to Betelgeuse, as if observing the Little Dog on a tether to his master, Orion.
Half an hour after Procyon (Greek for “before the dog”) rises, look to its right for magnificent Sirius (Canis Major) to clear the horizon. Brilliant, bluish Sirius (Greek for “scorcher”) is the brightest true star in Earth’s sky and can be found below Procyon most of the night. The Belt stars point to Sirius, which is also known as the Dog Star. When seen to the left of Rigel (Arabic for “foot”), the Dog Star appears to heel to Orion, following the Hunter, like Procyon.
As Sirius rises in the southeast at nightfall, planet Venus, aptly named for the goddess of love and beauty, holds court in the southwest. When enjoying Sirius in early evening, pivot to your right to meet Venus. For a good view of the planet, look by 8:00pm.
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