Minnesota Starwatch is a newsletter describing the night sky in the Midwest.
Updated monthly, it is produced by the
Minnesota Starwatch for January 2016
by Deane Morrison
The new year opens with four of the five bright planets in the morning sky. By the end of January, all five will be strung across the predawn firmament. The month starts with Venus blazing away in the southeast an hour before dawn. Dimmer Saturn is to the lower left, and Antares, the bright red heart of Scorpius, smolders to the lower right of the ringed planet. Both quickly climb past Venus. Look on the 6th and 7th for a lovely lineup of Venus, Saturn, and a waning moon, and also on the 9th, when Saturn appears less than a moon's width from the brilliant planet.
High in the southwest, Jupiter also shines brightly. About midway between Jupiter and Venus is a pair of objects: reddish Mars on the left and Spica, the brightest star in Virgo, on the right. These two move apart as the days go by. Also, by the 25th you may be able to spot Mercury just above the horizon, below and left of Venus. That gives us a planetary string in the order (southeast to southwest) of Mercury, Venus, Saturn, Mars and Jupiter. The lineup will continue into the early days of February.
In the evening sky, the lovely winter stars are in full glory. Sirius, the brightest of all, shines from Canis Major, at the base of the dazzling array. Grab a star chart and pick out the other beacons: Procyon in Canis Minor, Pollux and Castor in Gemini, Capella in Auriga, Aldebaran in Taurus, and Rigel and Betelgeuse in Orion.
At 4:49 p.m. on the 2nd, Earth reaches perihelion, its closest approach to the sun in its orbit. We will be 91.4 million miles from our parent star&emdash;unfortunately, not nearly close enough for us to feel any extra warmth.
It is perhaps lucky that perihelion falls during the northern winter. As it orbits the sun, Earth's speed averages about 30 kilometers per second. But that figure varies by plus or minus one percent, with the highest speed at perihelion in January and the lowest at aphelion, our farthest point from the sun, in July. Thanks to our greater speed during the northern winter, we spend less time in that part of our orbit and more time in the part where the Northern Hemisphere is tipped toward the sun. You can verify this by counting the days from the March equinox to the September equinox, and then again from the September equinox to the March equinox. You'll find we get several more days of spring and summer than of fall and winter.
January's moon reaches fullness at 7:46 p.m. on the 23rd. That's less than three hours after moonrise, so this one will be another almost perfectly round beauty. Algonquin Indians called January's full moon the wolf moon, for the hungry howling outside their villages. This year it follows the knot of bright winter constellations across the night sky.
Duluth, Marshall W. Alworth Planetarium: www.d.umn.edu/planet
Twin Cities, Minnesota Institute for Astrophysics (during fall and spring semesters): www.astro.umn.edu/outreach/pubnight
Check out the astronomy programs at the University of Minnesota's Bell Museum ExploraDome: www.bellmuseum.umn.edu/ForGroups/ExploraDome/index.htm
12/21/15 Contact: Deane Morrison, University Relations, (612) 624-2346,
Find U of M astronomers and links to the world of astronomy at http://www.astro.umn.edu.