Starwatch: Big Winter Triangle is a perfect night sight
The stars of the celestial dome we see night after night, at least when the clouds decide to stay out of the way, are random arrangements of stars in a huge range of brightness. Of course in the urban-lit areas you only see the brighter ones.
I actually enjoy how the stars are randomly thrown against the sky. To me it makes stargazing more of an enjoyable challenge. People throughout the eons tried to make sense of what they saw, looking for "pictures" made up by the stars that represented characters in stories or legends or mythologies. These pictures, in most cases, demand an incredible level of imagination to see them as what they are conceived to be. These pictures in the stars are what we call constellations.
Most of the tales that are best known in this part of the world are spinoffs of Greek and Roman mythology. While different cultures have their own unique mythology, all the constellations are pictures of the characters that make up these soap operas of the night sky. You have to constantly remind yourself, though, that as you witness the stars and constellations they aren't all painted on a flat canvas. You are really looking at a three dimensional field. There's no such thing as chartering a spacecraft in the future and zooming out to the constellation of Orion the Hunter. That can't happen, since the stars that make the mighty hunter are widely varying distances from your backyard.
Some constellations, though, do display some pretty unique geometrical shapes that astronomers call asterisms. The connecting lines of stars in the constellation Cassiopeia the Queen resembles a giant W in the heavens that's now hanging nearly upside down in the evening in the northwest. The right side of the constellation Leo the Lion, now rising in the east after twilight, outlines a backward question mark.
The constellation Auriga the Chariot Driver, now shining very high in the southeast sky, looks like a lopsided pentagon. One of the best patterns is that of the seven stars that make up the rear end and tail of Ursa Major the Big Bear. Those stars also make what we call the Big Dipper, presently standing diagonally on its handle in the low northeast sky.
There are much larger asterisms in the sky that use stars from several adjoining constellations. These can be great tools in learning constellations. One of these is known as the Summer Triangle, made up the brightest stars from three separate constellations. At the corners are Vega, the brightest star in the constellation Lyra, Deneb, in the constellation Cygnus the Swan, and Altair, in the Aquila the Eagle. Each one of these stars is the brightest shiner in its home constellation. The Summer Triangle is so easy to see at a glance in the summer and autumn sky and can be a very good tool in helping you find your way around that part of the celestial theater.
The very best asterism of the night sky right now — at least in this stargazer's opinion — is the Winter Triangle, now on display January winter evenings in the southeastern sky. Without stretching the truth a bit, the Winter Triangle is a perfect equilateral triangle made up of three bright stars from three separate constellations.
Unless you're viewing from right under a street lamp, you should have no trouble spotting it. As you can see in the diagram, it's made up of the stars Betelgeuse, from the constellation Orion the Hunter, Procyon, the brightest star in the constellation small Canis Minor the Little Dog, and Sirius, the brightest star in Canis Major the Big Dog.
Sirius also happens to be the brightest star in the night sky. These three stars are the brightest star-like luminaries in that part of the sky, with the exception of the very bright planet Jupiter shining off to the upper left.
Sirius and Procyon are almost twice the diameter of our sun and are more luminous than our home star, but the main reason they're so bright is they're relatively close to the Earth. Procyon is 11 light years away and Sirius is just over 8 light years away.
Sirius can be a whole lot of fun to view through even a small telescope. That's because it never gets up very high in the sky and its light has to travel through much more of Earth's blurring atmosphere to reach our eyes. If upper air winds are strong and there's a lot of turbulence, Sirius can appear as a changing kaleidoscope of colors as its light rays get bounced around.
The third star of the triangle, Betelgeuse, is a huge star well over 500 light years away. This super red giant star is almost a billion miles in diameter and sooner or later will burst in a colossal supernova explosion, maybe within a million years, if you feeling like waiting up for it. Until then, you can see the upper right hand member of the Winter Triangle shining brightly, sporting an easily seen reddish hue. I'll have a lot more on Betelgeuse next week in Skywatch
It's just amazing to me that these three stars that make up the absolute perfectly proportioned Winter Triangle just happen to be positioned the way they are in the winter sky. Coincidence? Or divine intervention? That's your call!
Check out the full moon passing by Jupiter in the southeastern evening sky this week. On Tuesday, the moon will pass about 6 degrees to the right of Jupiter. Enjoy the hugging, early-morning risers!
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, "Stars, a Month by Month Tour of the Constellations" published by Adventure Publications.
The Rochester Astronomy Club welcomes new members and puts on public star parties. Their website is www.rochesterskies.org.