The sky in December 2019 — Have a holly jolly starwatching season
There’s magic in the air this holiday season and there’s also magic in the Marshall night skies. These long nights are blessed with some of the best constellations of the year. Bundle up, get out that comfy reclining lawn chair, brush away the snow if you have to, and enjoy the cold clear night delights. You can get an early start with the early sunsets of the year.
The Venus, Saturn, and Jupiter show dominates the first week of December. In evening twilight look for a super bright “star” in the very low southwestern sky. That star is actually the planet Venus about 139 million miles away from Earth. Just to lower right of Venus look for another almost as bright “star.” That’s actually Jupiter, 567 million miles away. As twilight fades to a close another fairly bright “star” will pop out just to the upper left of Venus. That’s actually Saturn, a little over a billion miles away. As the first week of December continues Venus and Saturn will get closer and closer to each other while Jupiter drops out of sight. Of course, none of these planets are anywhere near each other physically but are nearly in the same line of sight.
On Dec. 10, Venus and Saturn will almost be “touching” each other in the very low southwestern sky. Saturn will be less than two degrees to the upper right of Venus. You don’t want to miss this! Be sure to look very early in the evening toward the end of evening twilight because shortly after evening twilight both planets will set below the horizon. Unfortunately it won’t be much of show with telescopes or binoculars since both planets will greatly suffer the blurring effects of Earth’s thicker atmospheric layer close to the horizon. Later on this month on Dec. 28 there’ll be a heck of a nice conjunction between Venus and the new crescent moon in the evening twilight. The moon will be parked just below Venus. Don’t miss it!
Full moon this month is on Dec. 12 and that’s too bad because that’s around the time of annual Geminid meteor shower, one of the best of the year. The peak of the showers are the night of Dec. 13-14. In the countryside especially it’s possible to see over 100 meteors an hour but the moonlight will whitewash all but the brighter ones. It’s still worth looking though. The Geminids are produced by debris left in the wake of passing asteroid known as 3200 Phaethon.
Even though it’s December we can still see a few summer constellations in the early evening western sky. Look for the “Summer Triangle” of stars; Vega, Altair, and Deneb, the brightest stars in their respective constellations Lyra the Lyre, Aquila the Eagle, and Cygnus the Swan. Deneb, the highest star in the summer triangle is at least 1,500 light-years away and marks the tail of swan. Within the constellation Cygnus you can easily see what’s known as the Northern Cross asterism. During the holiday season the cross is standing nearly upright above the northwestern horizon with Deneb at the top of the cross. This is really the last call for these summer constellations as the Earth is gradually turning away from that part of space in its orbit around the sun.
The great horse Pegasus is riding high in the south-southwestern sky with Cassiopeia the Queen, the one that looks like a bright “W” in the high northern sky. The Big Dipper is still very low in the northern sky, but you’ll notice that from night to night it will gradually get higher, standing diagonally on its handle. The Little Dipper is hanging by its handle above the Big Dipper, with Polaris the North Star at the end of its handle. Because Polaris is shining directly above Earth’s North Pole, it appears that all of the stars in the sky revolve around Polaris once every 24 hours, including our sun.
The later you stay up in the evening the more you’ll see of the best part of December skies rising in the east. By 8 to 9 p.m. you’ll easily see Orion the Hunter, that wonderful winter constellation, rising in the east. Its calling card is the three bright stars in a row that make up Orion’s belt. Preceding Orion are the bright autumn constellations Taurus the Bull, with the wonderful Pleiades star cluster, and Auriga, the constellation that looks like a lopsided pentagon with the bright star Capella. Auriga’s supposed to be a retired chariot driver turned goat farmer. Just to the north of Orion is the constellation Gemini the Twins, with the bright stars Castor and Pollux in position on the forehead of the Twins. I call this part of the sky “Orion and his gang.”You can have lot of fun with your Sky Guide app exploring December night skies!
Saturday, Dec. 21 marks the winter solstice, with the sun directly overhead at noon. The longest night of the year in the northern hemisphere and the shortest night in the southern hemisphere. At noon on Dec. 21, the sun shines overhead at noon over the tropic of Capricorn, south of the Earth’s equator. From now until the late next June the sun’s path among the backdrop of stars will slowly migrate northward and in the northern hemisphere the sun will appear higher and higher in the sky.
Have a fun filled and star filled most wonderful time of the year!
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul.