Astronomical Events for December

The name for December is derived from the Latin “Decem” meaning “ten”. It was the tenth and last month in the Roman calendar.
The traditional full moon name for December is the “Cold Moon”. Other common names include the “Oak Moon”, “Christmas Moon” and the "Long Night Moon". This month is also “Moon before the Yule”. This name applies when the full Moon comes before Christmas. The Lakota Sioux called it the “Moon of the Popping Trees”. The Cheyenne named it the “Big Freezing Moon”. The Taos call it the “Night Moon” and to the Wisham it was “Her Winter Houses Moon”.
  • New Moon: December 21
  • Closest to Earth: December 24 (226,675 miles super-size moon)            
  • First Quarter Moon: December 28
Planets Visible:
Early evening:
  • Mars will be low in southwest (Mars will appear in about the same position all month as it did last month). Watch the background stars pass by.
 Morning before sunrise:
  • Jupiter, look west  all month
  • Saturn rises with the Sun at the beginning of the month and is well placed low on the eastern horizon the last two weeks of the month
  • Mercury and Venus spend most of the month behind the Sun. Both will be somewhat difficult to see this month. For Venus look west very low on the horizon just after sunset starting around Christmas Eve.  Start looking for Mercury five days later. It will be below Venus and a challenge to see. Next month the two will be putting on a show.Sun:
  • December 18: Sun enters the astronomical constellation Sagittarius.
  • December 21: The Sun enters the astrological sign Capricorn.
  • December 31: Sunrise 7:20am MST, Sunset 4:44pm MST                                                                                                                                                                                                                      
  • December 8: Earliest Sunset 4:34pm MST (by just a few seconds). Sunset times are the same (nearest minute) from December 6 to December 11.
  • December 19: Satrunalia, an ancient Roman festival believed to be related to the date we celebrate Christmas
  • December 21: Winter Solstice occurs at 4:03pm MST
  • December 25: Equation of time is zero. (Sundials need no adjustment to account for the variations in the Earth’s orbital speed)
  • December 13-15 late evening: Geminid meteors peak. Best observe before moonrise (13/14 11:39pm MST, 14/15 12:35am MST. Meteors will be radiating from the east.
 Special Events:
  • December 19 morning: A crescent moon will be above Saturn. Both are in the constellation Libra the scales. Look east around 6:15am MST (sunrise 7:15am MST)
  • December 24-25: the Moon is next to Mars on December 24, and below the Moon on December 25 low in the west southwest horizon after sunset. Note Look before 7:00pm. Mars sets around 8:00pm.
  • December 27: Chamberlin Observatory open house weather permitting. The observatory’s 20” telescope and telescopes belonging to members of the Denver Astronomical Society will be available for viewing. Click here for more information. Bring that new Christmas telescope if you need some help. There will be a lecture on how to use your new telescope starting a 7pm.
Historical Trivia
  • December 25, 1968: Apollo 8 achieves first lunar orbit by a manned craft.
  • December 15, 1970: The Soviet lander Venera 7 lands on Venus, the first lander to make a soft landing on another planet. The lander measured a surface temperature of 869 °F and an atmospheric pressure of 90 atmospheres. That’s equal to the pressure at a depth of 3050 feet in the ocean, well below the crush depth of most submarines. The lander lasted 23 minutes before succumbing to the extreme temperature and pressure.
 Wish you clear skies

The Star Spangled Radio Hour

KEZW and our friends at the Glenn Miller Archive at the University of Colorado present the Star Spanged Radio Hour, Saturday night at 6pm.  Rick and Dennis Spragg introduce live big band radio broadcasts from the 30s and 40s that haven't been heard since they originally aired.  It's our time capsule from the big band era and you can only hear it on AM 1430!  Miss a show?  Click here.

Rick's Thought for the Day


Thought 12.19.14

"Peace on Earth will come to stay when we live Christmas every day"

Helen Steiner Rice