The Celestial Sphere

By Matthew Johnson

We begin the month of December and continue into January with long nights, reaching a maximum on the evening of the winter solstice on Dec. 21—with 14 hours and 56 minutes of darkness and only 9 hours and 4 minutes of daylight. After the 21st, each day grows a few minutes longer until the summer solstice in June. The occasion has been acknowledged throughout history by cultures displaying forms of lighting and greenery celebrating a “return of the sun.”  

The winter solstice occurs at 5:02 a.m. During the winter solstice, the South Pole of the Earth is tilted to its greatest extent toward the sun, which will have reached its southernmost position in the sky, the sun being below the equator and directly over the                                                                      Tropic of Capricorn at 23.44 degrees south latitude. The solstice marks the first day of winter (winter solstice) in the Northern Hemisphere and the first day of summer (summer solstice) in the Southern Hemisphere. During this time, the North Pole experiences 24 hours of darkness and the South Pole 24 hours of daylight. 

Planets: 

As darkness sets in and the constellations begin to appear in the night sky, the planet Venus, at the beginning of the month, will shine at its brightest around 15 degrees high in the night sky in the southeast. On the 6th it will be just above the crescent moon. Additionally on the 6th there will be a grouping of the planets just after sunset. From lower right to upper left stand the planets Venus, Moon, Saturn and Jupiter.  This particular grouping will continue on Dec. 7 and 8, but there will be a slight shift with the moon, now second from the top just below Jupiter. From Dec. 24 to Jan. 2, Mercury will stand bright, visible below Venus. Mercury will be to the left of Venus from Dec. 29-31. 

Mars reappears in the morning sky in Libra. Mars rises two hours before the sun and is located low in the southeast as twilight begins. On the last day of December, the waning crescent moon will be slightly to the right and above Mars and just above the red giant star Antares in Scorpius. Antares will appear slightly brighter than Mars. This is a beautiful configuration in red.

Meteor showers:

There are two major meteor showers during December. There is the Geminid shower, which occurs from Dec. 4-7 with a peak on the night of the 14th, and the Ursid meteor shower, which occurs from Dec. 17-26, peaking on the 22nd. There will be a large waxing gibbous moon in the constellation Pisces during the Geminid’s peak. This will result in the moonlight interfering until the moon sets just after 3 a.m. The Geminid shower is one of the best showers of the year, with rates up to 150 per hour. They will appear to radiate from the constellation Gemini up near the zenith. The  Ursid meteor shower will be much too affected by the waning gibbous moon and very few meteors are predicted for this year’s Ursid shower. 

Moon phases for December:

Dec. 4: New moon (no visible moon). The best time of the month to observe faint objects such as distant galaxies. 

Dec. 10: First quarter (right half of moon illuminated). Moon is waxing.

Dec. 18: Full moon (Cold Moon).

Dec. 26: Last quarter (left half of the moon illuminated). Moon is waning. 

Moon phases for January 2022:

Jan. 2: New moon (no visible moon). The best time of the month to observe faint objects such as distant galaxies. 

Jan. 10: First quarter (right half of moon illuminated). Moon is waxing.

Jan. 17: Full moon (Wolf Moon).

Jan. 25: Last quarter (left half of the moon illuminated). Moon is waning. 

December’s full moon was known by Native American tribes as the Cold moon 

because this is the time of year when the winter air settles in and the nights become long and dark. This moon has also been called the Long Nights Moon, since it is close to the date of the winter solstice and is the moon before Yule.
January’s full moon was known by Native Americans as the Wolf Moon because wolves were more likely to be heard calling at this time. The Assiniboine people of the Northern Great Plains called January’s full moon the Center Moon because it marked the middle of their coldest season. To the Algonquin, it was the Freeze Up Moon and to the Dakota the Hard Moon, referring to snow forming a crust on its surface. 

Comet:

There is the possibility of the naked-eye appearance of comet C/2021 A1 (Leonard). This comet was discovered by Greg Leonard in January 2021 at the Mount Lemmon Observatory. Leonard should show up by the second week of December and will rapidly fade by the beginning of January. It is classified as a long period comet and will return in some 80,000 years. Comet Leonard is predicted to display a blade or fan type of tail with a greenish-blue aspect. The best effect of the comet’s tail will be on the nights of Dec. 9 and 14. Binoculars may be necessary to see details of the comet. 

There has been confusing information as to when to view Leonard. It will be visible both after sunset and before sunrise in two different areas of the sky. Start observing in the southeast just before dawn up to Dec. 12; after the 12th, switch to early evening and look low in the southwest. From Dec. 3-6 the comet will appear in the early morning near the star Arcturus. Follow the arch of the stars of the handle of the Big Dipper; moving away from the dipper you will locate the brilliant topaz Arcturus. Look for the comet just above Arcturus from Dec. 1-4, next to Arcturus on the 5th and to the left and below Arcturus from Dec. 6-12. Viewing the comet will be best at a location that has a low horizon and as little light pollution as possible. 

Visit astronomy.com/skythis in December for viewing charts of comet Leonard for the latter half of December.