The vividness and clarity of January’s night skies are enough to make a skywatcher
forget the cold long enough to take exploratory plunges into reinvigorating celestial sights.
When you’re outside around 8 p.m. on any clear night, it’s practically impossible to miss
the three star belt of Constellation Orion, the enormous hunter, looming in the southern sky. The constellation reaches its highest point for the year (culminates) when its center strikes the north/south meridian at 9 p.m. Jan. 25, putting it in the year’s best viewing position for everything from a naked eye to high-powered astrophotography telescopes.
The eight bright stars that define the asterism are mostly young, blue or blue-white
supergiants either flying solo or as multiple star systems ranging from 244 to 2,000 light years distant. The chief exception is the goliath’s northern shoulder star Betelgeuse, an immense and pulsating red supergiant. Betelgeuse, an asymmetric runaway star nearly a billion miles wide, is so large that if it were in the sun’s place, its variable “edge” would reach farther than the orbit of Jupiter.
Look beneath the three belt stars — from the east Alnitak, Alnilam and Mintaka — to locate Orion’s sword. Its central “star” is magnitude +4.0 Orion Nebula, a reflection/emission region of massive star formation. With averted gaze, skywatchers should be able to see the ghostly green tint of the nebula even in some light-affected backyards. Use a 5-inch or larger telescope to observe the six stars of the Trapezium Cluster, an exquisite glittering cluster of new stars about 15-30 times the mass of the sun.
In total, there are 81 stars of Constellation Orion. Orion is just one of many dazzlers in this vast swath of sky, with 2023 starting its first week with something of a sensation.
Mars, brilliant at magnitude −1.07, lingers less than 10 degrees from red giant Aldebaran, the eye of Taurus, all month. Mars is rapidly retreating since its Dec. 7 opposition, standing tonight at about 58.8 million miles (94.6 million km) away, ending January at 81.4 million miles (131 million km). By Independence Day, the god of war will be low in the west and greatly diminished, setting early at magnitude +1.75 and 207.3 million miles (333.4 million km) distant.
Enjoy its high mid-evening transits while you can. Aldebaran is along the line of sight to the Hyades, an open cluster whose brightest stars form the V-shaped face of the bull of Zeus. To its west is the Pleiades, an open star cluster of 14 naked eye blue giants, which contrasts markedly with the ruddy hue of the god of war. Though outshined by neighboring Seven Sisters, the Hyades is actually nearer at 153 light years. Use
The Red Planet pairs twice with the moon this month. The two orbs come within 2½
degrees of one another Tuesday [Jan. 3]. Around 10 p.m. Jan. 30, the moon barely misses occulting (covering) Mars by a mere fraction of a degree. Their closeness will be remarkable nonetheless. Skywatchers in southern Colorado and points south have a better chance of catching the occultation.
Another intimate pairing, a planetary conjunction in fact, occurs with Venus and Saturn
each night about half an hour after sunset Jan. 22-24. The closest conjunction for the year sees Venus, 76 times brighter, come within ½ degree of Saturn. The difference in brilliance is such that observing Saturn, awash in Venusian splendor, may require binoculars.
There’s no particular celestial, meteorological or mythological reason that the New Year
begins Jan. 1. It’s coincidental that the brightest star in the night sky, Sirius the scorcher,
strikes the meridian at exactly midnight New Year’s Day. That Jan. 1 is the first day of the year is the result of Gaius Julius Caesar’s reforms of the Roman calendar. The Roman calendar was based on the lunar cycle having 304 days of 38 market cycles, leaving 50 days as unorganized wintertime. After consulting with mathematicians
and astronomers, Caesar’s edict involved the addition days and shuffling the months. He pronounced that Janus, the god of beginnings, ends and transitions (as well as wars and peace, doors and passageways) would be the patron of the first month of the year.
Janus, strictly a Roman god, is depicted as having two faces, one facing backward, the other forward. The first modern New Year’s celebration was Jan. 1, 45 B.C.E. The Julian calendar did much to address many of the intercalary artifices — manipulations
— necessary to correct for the errors inherent in the Roman calendar. However, it calculated that the length of one year was 365.25 days, incorrect by about 11 minutes, an error that led to calendrical “drift.” The Julian calendar was tweaked by Pope Gregory XIII in 1582, leaving the Gregorian calendar that most countries use today in their civil purposes.
The moon is full at 4:07 p.m. Jan. 6 and is called the Full Wolf Moon.