I love hanging holiday lights all over the outside of my house and all over my trees and bushes. Some of my neighbors think of me as the local "Griswold" of the neighborhood. I don't have as many lights up as Chevy Chase had in the classic holiday movie "National Lampoon Christmas Vacation," but appropriately I have a lighted star on a pole on top of my garage. I also have the plastic lighted Santa Claus, lines of flashing candy canes on both sides of my driveway and much more. Anyone want to help me with my electric bill in January?
The night sky has a big touch of Griswold this time of year with all the bright stars and constellations of winter like Orion the Hunter and Gemini the Twins. This winter, we also have the extremely bright planet Jupiter among them. As I told you last week in Starwatch, Jupiter is the closest it's been to Earth in more than a year and is by far the brightest star-like object. You can't miss it rising in the early evening sky.
If you happen to get a telescope for Christmas, make Jupiter one of your targets with its four brightest moons and the cloud bands that stripe the disk of the largest planet of our solar system. Just make sure you let your telescope and all its eyepieces sit outside at least a half hour before you use it so the optics can adapt to the cold. Otherwise, you'll get some really funky images.
Unfortunately, there really aren't any constellations or constellation stories that have much to do with Christmas. Most of the names and stories we know of for constellations around here involve early Greek and Roman mythology. The gods and goddesses never got into the holiday spirit and so there's not much celestial mistletoe and holly.
There is, however, a miniature but distinct symbol of the holiday season in the eastern sky, but you have to dig for it a little bit. It's called the Christmas Tree Cluster because that's exactly what it looks like. You'll need binoculars or a small telescope to see this celestial Christmas card and you'll have to wait until after 8:30 p.m. or so for it to be high enough above the eastern horizon. It might take a little work to find the Christmas tree cluster.
The Christmas Tree Cluster resides in a very obscure constellation, Monoceros the Unicorn. Forget about trying to truly see this constellation; it's just so faint and undefined. The best way to find it is use the bright constellation Orion the Hunter, perched diagonally in the southeastern sky. I know you've seen it before; It's the dominant constellation of winter with the three bright stars in a nearly perfect row that make up the belt of the mighty hunter.
On the upper left corner of Orion is a bright reddish-tinged star called Betelgeuse that marks the armpit of the hunter. On the upper right corner of Orion is the star Bellatrix, not quite as bright as Betelgeuse. Draw a line from Bellatrix to Betelgeuse and continue that line to the lower left about ten degrees from Betelgeuse. Ten degrees is about the width of your fist at arm's length. Scan that area with your binoculars or telescope and you eventually should find it. This coming week is a great week to find it because there isn't much moonlight in the sky.
Once you find it, you'll see the 20 or so stars are arranged in the shape of Christmas tree and it even has a couple of brighter stars that mark the top of the tree. Just like a lot of trees in local tree lots, it's not exactly a perfect tree, but hopefully it'll still add to your holiday spirit. The little starry tree will appear to point to the right in binoculars but in most telescopes, it'll appear to point left since the optics in most telescopes give you an inverted view of the heaven. It's brightest star is actually at the base of the tree.
The Christmas tree shape of the cluster is arguably a pleasant coincidence. The stars just happened to be arranged that way from our view of them from Earth. Like most open clusters, this group of young stars formed out of the large nebula of hydrogen gas, much like our sun did more than five billion years ago. These clusters of young stars hang out together for several hundred million years until gravity from other surrounding stars break these clusters up.
This Christmas tree cluster astronomically bids tiding of joy from a long way away at more than 2,600 light years. Just one light year equals almost six trillion miles. The light we see from it tonight left that cluster in 606 B.C. The famous British astronomer William Herschel discovered this cluster in 1783 near Bath, England, and more than 200 years later, its starry ornaments are still lighting up the tree. I wonder who pays that electric bill?
(Lynch is an amateur astronomer and is author of the book, "Stars, a Month by Month Tour of the Constellations." Contact him at mikewlynch@comcast.net.)