Minnesota Starwatch - January 2021
As the new year dawns, three of the five brightest planets are busy dropping out of view—Venus from its position as a morning planet, Jupiter and Saturn as ornaments of the evening sky.
Actually, the planets are only switching places. We’re leaving Jupiter and Saturn in the dust as we circle behind the sun, but when we come around in a couple of months we’ll find them in the morning sky. Likewise, speedy Venus is now heading behind the sun, but it will reappear as an evening planet in late spring.
In the last two weeks of January, Mercury pops up very low in the west-southwest. The sunset glow may obscure it, so have your binoculars handy. Mars, however, remains high but drifts slowly westward as the large knot of famous winter constellations closes in on it from the east.
These constellations won’t all be up until about three hours after sunset on the 1st, earlier as the month goes on. Atop the assembly sits brilliant Capella, in Auriga, the charioteer. At the bottom, even more brilliant Sirius outshines not only its fellow stars in Canis Major, the big dog, but every other star in the night sky. Sirius also is one point of the nearly equilateral Winter Triangle. The others are Betelgeuse, at Orion’s right shoulder, and Procyon, to the upper left of Sirius in Canis Minor, the little dog.
The morning of the 2nd, Earth reaches perihelion, its minimum distance—about 91.5 million miles—from the sun. We sweep through perihelion at top speed: 18.8 miles per second.
On the 6th, a last-quarter moon hovers above Spica, the only bright star in Virgo, the maiden, in the predawn sky. The next morning, the moon appears next to Spica. Off to Spica’s lower right is the skewed four-sided figure of Corvus, the crow. High to the left of Spica blazes Arcturus, the beacon of kite-shaped Bootes, the herdsman. An old moon rises near Antares, the heart of Scorpius, the morning of the 10th. If you go out 40 minutes before sunrise on the 11th, you may catch a very thin lunar crescent close to Venus.
January’s full moon shines the night of the 28th and follows the winter constellations across the sky.
The University of Minnesota’s public viewings of the night sky at its Duluth and Twin Cities campuses have been curtailed due to the COVIC-19 pandemic.