SKY GUIDE: This chart represents the sky as it appears over Maine during January 2020. The stars are shown as they appear at 9:30 p.m. early in the month, at 8:30 p.m. at mid-month and at 7:30 p.m. at month’s end. No planets are visible at chart times. To use the map, hold it vertically and turn it so that the direction you are facing is at the bottom. Sky Chart prepared by George Ayers.

The month of January is named for Janus, the Roman god of beginnings and endings, transitions and passages. He is depicted as having two faces, looking forward and backward at the same time.

This is the first full month of winter and we will probably have plenty of long and cold nights this month to enjoy the sparkling stars spread out all over the sky. The stars always seem brighter in winter because the air holds less humidity when it is colder. Most of the brightest stars in the winter sky are all arranged nicely in a rough hexagon, appropriately called the Winter Hexagon.

This entire hexagon is now above the southeastern horizon by 8 p.m. Once you can identify the eight bright stars in this hexagon (consisting of six constellations) and learn their distances from Earth, you can obtain a better three-dimensional view of this part of the sky.

We will start our little tour of the winter sky at the top of this hexagon with a star named Capella in the constellation of Auriga the Charioteer. At zero magnitude, this is actually a double star, each one of which is about 10 times the diameter of the sun. You can think of it as the “cap on the sky.” Capella is about 42 light years away.

Next up, we travel clockwise to Aldebaran in Taurus the Bull. This orange giant star’s name means “the follower” since it appears to be following the Pleiades star cluster across the sky. It is located 65 light years away and its diameter is about 40 times larger than our sun.

We will continue on to the next bright star, Rigel, which marks the left knee of Orion the mighty hunter. This is an extremely powerful blue super giant star that is 74 times the diameter of our sun, but it is only a few million years old. Rigel is the farthest away of any of the Winter Hexagon stars. It is 864 light years away. That is an easy number to remember because the diameter of our sun is 864,000 miles.

Now we come to the brightest star in the whole sky and the closest one to us in this hexagon. That is a star named Sirius in Canis Major, the large hunting dog of Orion. It shines at magnitude minus 1.4 and is located only 8.8 light years away. Sirius also has a companion star, a white dwarf star called Sirius B, which orbits around Sirius in an elliptical orbit every 50 years. It will be far enough away from Sirius now until 2035 to be able to discern it in a good amateur telescope. It is 10,000 times fainter than Sirius and it is only the size of Earth.

We then continue to the faintest of these eight stars, Procyon in Canis Minor. Procyon is the second-closest star at 12 light years away. Procyon also has a much fainter white dwarf star orbiting around it every 40 years.

There are two stars left to complete our hexagonal tour, Castor and Pollux in Gemini the Twins. In mythology, they are the sons of Zeus; Pollux is the immortal twin and Castor is the mortal one. We get to Pollux first. It is a red giant star located 34 light years away. Castor is actually a six-star system located 51 light years away.

The other celestial highlights this month include Venus climbing higher into our evening sky, two asteroids at their best, and one of the best meteor showers that you have probably never seen.

Venus starts the year 25 degrees above the horizon at sunset and sets two hours, 45 minutes after the sun. It will finish January 34 degrees above the horizon and will set 3-1/2 hours after sunset. It also will get closer and brighter and less illumined by the sun as it catches up with Earth in its faster orbit around the sun.

We lost Jupiter and Saturn last month. Now Jupiter will show up again in the morning sky by the second week of January and then Saturn will reappear in the morning sky by the end of the month.

Two bright asteroids, 5 Astraea and 511 Davida, will reach opposition this month. 5 Astraea is 74 miles across and will reach 8.9 magnitude in Gemini in the Winter Hexagon on Jan. 21. Then 511 Davida is about 180 miles across and will reach opposition in Cancer, just to the east of Gemini on the 15th. You would need good binoculars or a small telescope to see them.

The best meteor shower that most people never heard of occurs every Jan. 4. These are called the Quadrantids, named after an extinct constellation, Quadrans Muralis. The radiant is in the Northeastern sky just below the Dippers and above Hercules. You could see over 100 meteors per hour this year since the moon will not interfere. Its peak is very narrow, only six hours or so, and the weather is not usually clear and it is usually very cold, so that is why most people have never seen this shower. This year we are perfectly placed on the East Coast to intercept this very narrow peak. It will be at its best between 2 a.m. and 6 a.m. on Saturday morning. Try to get some photographs of this amazing shower if it is clear this morning.

Jan. 1: On this day in 1801, Giuseppe Piazzi discovered the first and largest asteroid, Ceres, which is 600 miles in diameter.

Jan. 2: First quarter moon is at 11:47 p.m.

Jan. 4: The Quadrantids peak between 2 a.m. and 6 a.m. Mars is in the morning sky near Antares in Scorpius 45 minutes before sunrise.

Jan. 5: Earth is at perihelion, or closest to the sun today at 91.4 million miles.

Jan. 7: On this day in 1610, Galileo discovered 3 moons of Jupiter: Callisto, Io, and Europa. He would discover Ganymede, the largest moon in the whole solar system at 3,200 miles in diameter, six days later. The nearly full moon passes close to Aldebaran in Taurus tonight.

Jan. 8: Stephen Hawking was born on this day in 1942.

Jan. 10: Full moon is at 2:22 p.m. This is also called the Ice or Wolf moon.

Jan. 17: Last quarter moon is at 8 a.m.

Jan. 19: New Horizons was launched to Pluto on this day in 2006. It got to Pluto nine years later on July 14, 2015.

Jan. 24: New moon is at 4:43 p.m.

Jan. 28: The waxing crescent moon passes near Venus this evening a half an hour after sunset.

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