The crisp, dry air of winter offers exceptional transparency. In the mid-northern latitudes, the night now claims 14 to 15 hours of our 24-hour day.
After spending all day in an office, a school, or home, the spirit needs more than fresh air; it needs some fresh thoughts. What better time than from sundown to sunup to cultivate them?
Here are some night-sky highlights for the month of January.
First question to ask when stargazing: What's up with the moon? The first week of January there is no visible moon, and little moonlight the second week. The same holds for the last week of the month. But from Jan. 11 to 24, moonlight will be a factor in the evening sky.
A recommendation: On Friday the 17th and Saturday the 18th, the moon is full. If you have a ken for ice skating, nothing this side of the space shuttle puts you closer to the heavens than a frozen pond, deep in the woods under a full moon. (Here in New England this is often doable, and as far as I can tell, it's a Canadian birthright. If you have your doubts about Canada truly being a separate nation, just ask someone from Florida or Texas if they've "ever ice skated by moonlight.")
New Year's Eve revelers, instead of ringing bells and blowing horns at midnight, pop outside into the quiet. Find a dark spot in the backyard or surrounding woods and fields.
Look southwest toward Orion, the Hunter, with his three-star belt midway in the sky. From the belt, run your eyes on a northeast diagonal (left) to Orion's shoulder, and you'll pick out the reddish-colored star Betelgeuse.
Above and to the right of Betelgeuse spins Saturn. This would be an ideal time to take out that new Christmas telescope. Saturn's rings, pitched 27 degrees to our line of sight, are about as open as they can be. In fact, they won't be so angled for another 30 years. If you're a more serious amateur, Saturn transits the face of M1, the Crab Nebula, the night of Jan. 4.
Not just on New Year's Eve but throughout the month, look east from Orion for the brightest light in the sky. It's not a star, it's Jupiter (the ancient Greeks called planets "wandering stars"). A good pair of binoculars should pick up the four Galilean moons. Below and to the right of Jupiter is the brightest star that can be seen from earth: the dog star Sirius, visible from January to March.
And for those planning to greet the dawn this New Year, a spectacle begins after 4 a.m. as Venus and Mars, little more than five degrees apart, make their appearance. (Each day for the remainder of the winter, they will split farther away from each other.)
Venus is a brilliant light in the early morning hours. For those with tele-scopes, one of the more fascinating sights in our solar system is the phases of this inner planet. Sunrise is best, as the goddess's twinkling diminishes with increasing sunlight. On Jan. 11, her orb will appear half-lit in a telescope.
And for anyone far from city lights, if there's snow on the ground (and no moon, of course), just stand in a secluded wood before dawn and you'll see a faint but discernible shadow cast by this morning star.
By Jan. 15 the red star Antares will join Venus and Mars in the predawn night. It will be visible just beneath Mars, displaying an even dustier reddish tint. Antares means "against Mars." More on Mars next month as it begins its closest approach to earth in more than 50,000 years, culminating on Aug. 28.
One final note: Next month earth will be at what astronomers call perihelion (closest to the sun). Why so cold then, you ask, if our blue planet is as near the sun as it gets? Remember, it's the tilt of the earth relative to the sun, not our proximity, that causes the seasons. As the northern latitudes rock back and the southern latitudes tilt forward, the sun's rays focus more intensely southward. As a result, theydiffuse over the earth in the northern latitudes, lessening their heat-bearing properties.