Orion, Sirius and Pegasus highlight December’s sky


Greetings everyone! It’s been quite a week for big news in the solar system. Last Monday and Tuesday we had the closest approach of Jupiter and Saturn in almost 400 years. Of course, although they looked extremely close together in Earth’s skies, they were still millions of miles apart. They were simply lined up from our point of view.

And don’t worry if you missed it because although Jupiter orbits the sun at 30,000 mph, it’s far enough away that it doesn’t move very fast in our sky. Saturn and Jupiter will be quite close together for the rest of the month. And if you think 30,000 mph is fast, just remember that your personal spaceship that you ride every day of your life orbits the sun at 66,000 mph!

Jupiter and Saturn aren’t your only evening planets. Mars is almost straight overhead, and the waxing moon skimmed past our red neighbor on Christmas Eve. And oh, by the way, Merry Christmas!!

There was a seasonal marker this week too. Winter solstice, the first day of winter was on Monday and of course winter solstice is the shortest day of the year. The day length on Monday was 11 hours and 20 minutes which is Guam’s shortest day. But loyal readers of this column know that in December every other day is also 11 hours and 20 minutes long. Lots of shortest days!

The sun reached its farthest point south on the solstice when it set at 246 degrees. Due west is 270 degrees, so the sun was 24 degrees to the left of due west on Monday. Go out any night this week and watch the sun set along your personal horizon. It will be setting very close to its farthest point south. Then on Christmas, go outside in your shorts and enjoy another beautiful tropical sunset.

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Our December skies are beautiful too. After it gets dark, turn around and face east. You’ll see the sky’s most famous constellation, Orion the Hunter and if you watch the eastern horizon for only a little while after 7 p.m., you’ll see a very bright star glide up out of the southeastern ocean. That’s Sirius, the sky’s brightest star. Sirius is in the constellation Canis Major the Big Dog and the dog is Orion’s hunting companion.

I call December’s sky the first-grade sky because it’s full of shapes and letters. See if you can find these objects. First find a square. To do it look straight overhead and slightly to the west at 7 p.m. That’s the Great Square of Pegasus. Now look very close to the western horizon and find a large bright triangle. That’s the Summer Triangle. Next is the letter M. Find it by measuring four fist-widths above the northern horizon. That’s Cassiopeia the Queen. Last, find the letter V by measuring four fist-widths above the eastern horizon. That’s the head of Taurus the Bull.

Guam’s skies are unique and magnificent. I hope you have the best Christmas ever and that next year will be wonderful. I also hope you plan to do a lot of skygazing!

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