The coldest time of year brings the brightest stars to the sky. Sparkling in the east and southeast after dinnertime are Orion and the Big and Little Dog Stars: Sirius and
Mars will probably be the first thing to catch your eye. Just a couple of weeks ago it made its closest pass by Earth until 2016, and it remains nearly that close. Mars is called the Red Planet, but it's actually pale yellow-orange. Even so, the color is obvious enough to help identify it.
At the lower right of Mars is wintry Orion, the legendary Hunter, with Mars-colored Betelgeuse marking his shoulder. The orange of Betelgeuse contrasts with the icy white of Rigel, Orion's upraised foot. Midway between Betelgeuse and Rigel is the Belt of Orion: a row of three stars lined up nearly vertically.
A striking color contrast exists between Mars and Sirius, which is rising into view far below Orion's Belt. Mars and Sirius are the two brightest points currently in the evening sky, evenly matched rivals for brilliance. Sirius is hotter than our mild, yellow Sun, so it shines white with a touch of blue, the color of a welder's torch.
But when you see Sirius rising, sparkling through bare branches around 7 or 7:30 this week, all bets are off. On many winter nights, the air shimmers with high-altitude turbulence, making Sirius twinkle with vivid flashes of color: red, green, yellow, orange, blue. Binoculars show this especially clearly.
These colorful twinkles, of course, have nothing to do with the star itself, which is 8.6 light-years away. The tiny temperature ripples causing them may be no more than a few thousand feet from your eyes.
Poetry and reality
Astronomy, like much of life, comes with two sides. There's the scientific side, all about the mind-blowing realities of the things we see far off in the depths of space. And there's the aesthetic side, the realm of poetry and imagination regarding starry nights as seen over your own backyard. Amateur astronomy combines both sides. This is an outdoor nature hobby, with as much room for mixing science and aesthetics as butterfly hunting or wilderness exploring. Some amateur astronomers specialize in one side, some in the other; most combine handfuls of both.
Count me among the mixers. I never tire of learning new details about how a star like Sirius works: its internal structure, the ways it cooks up its nuclear energy, its subtle surface workings that give it quite a different life from our sun. And I enjoy the tales of inspiration, heroic quests, dead ends, and years of patient diligence by which each little scientific detail was pieced out. From this point of view, Sirius's colorful twinkling due to earth's air is just a distracting annoyance. But how pretty it is! New England winters wouldn't be the same without it.
After a lifetime of astronomy enthusiasm, I can rattle off the vital statistics about scores of stars overhead, scientific facts that make each one a unique object living in its own domain far off in space.
At the same time, each constellation carries meanings for me from seeing it in special earthly settings, over a moonlit snowfield, between trees in a summer forest clearing, from a lakeside camp, over the garage by my childhood driveway.
And from between dark tombs in the Newton Cemetery, where as a child with sky guidebook, red flashlight, and binoculars, I went hunting for good skywatching spots with no bright lights. Trespassing was forbidden after dark, but that just added to the adventure.
So forget the idea that you need a physics degree to be an amateur astronomer. You just need a love of nature.
Although, if you ask scientists what they did as children, very often they will talk about spending a lot of time in nature. The two really do go together.
Whole-sky maps
Easy-to-use maps of stars and constellations across the entire evening sky are available at: SkyandTelescope.com/howto/basics/3308331.html.
Alan M. MacRobert is a senior editor of Sky & Telescope magazine in Cambridge (SkyandTelescope.com). His Star Watch column appears the first Saturday of every month.
