The Visible Planets
Mercury slowly climbs back into our early morning southeastern sky during the month of December, starting around December 12. Mercury appears highest in our predawn southeastern sky from around December 18 and 24 and is at its point of greatest western elongation from the Sun on December 25. By the end of the month, Mercury scurries lower in our southeastern sky only to disappear in the glare of the rising Sun by the first week of January 2025.
Venus is seen shining brilliantly above the south-southwest horizon after sunset this month. Look for the thin waxing crescent Moon below bright Venus after sunset on December 4.
Mars rises along the northeastern horizon about 2 hours after sunset. Watch this reddish planet brighten amongst the faint stars of the constellation of Cancer, the crab, through the month as the distance between Mars and the Earth decreases. Mars will appear stationary amongst the stars of Cancer, on December 7, and then will move westward (retrograde) amongst the stars. Mars will be at its point of opposition, nearest the Earth, on January 16, allowing for some exception views of Mars though a telescope this month and next month. Through the evening hours of December 17 to the morning hours of December 18, look for a close conjunction of Mars with the waning gibbous Moon.
Jupiter now rises in the northeast at sunset and sets in the northwest at sunrise, moving in a high arc across the southern sky through the night. It is at its point of opposition, and its closest distance to the Earth of 34 light minutes, on December 7. Jupiter continues to be found amongst the stars of the constellation of Taurus, the bull, and can be seen to be moving in a westward (retrograde) path through the constellation this month. On the nights of December 13 and 14, the waxing gibbous Moon will join Jupiter in Taurus. As Jupiter is at its closest distance to the Earth this month and as it can be found high in the southern (nearly 60 degrees) when it transits, the views of Jupiter through a telescope will be spectacular this month!
Saturn is found about 30 degrees above the southern horizon at sunset and then sets about six hours later in the southwest. Through the month, Saturn continues to be seen amongst the stars of Aquarius, the water bearer. Saturn can be found just above the waxing crescent Moon and then first quarter Moon on the nights of December 7 and 8. Saturn will still be a highlight of weekend evening observing at the RASC Observatory at the TELUS World of Science-Edmonton.
Moon Phases
December 8 First Quarter Moon
December 15 Full Moon (The Cold Moon)
December 22 Last Quarter Moon
December 30 New Moon
Special Events
International Space Station (ISS) Observable Passes
During the month of December there will be one evening pass of the ISS on December 2. From December 12 through till December 28, ISS passes move back to our predawn morning sky hours. Exact times of these passages for your location can be found by visiting the website http://www.heavens-above.com or by using satellite tracking smart phone apps like Sputnik or Spot-the-Station.
December 7 Jupiter at opposition!
December 9 Royal Astronomical Society of Canada (RASC) Edmonton Centre meeting
Live in the Zeidler Dome at TWOSE and presented virtually through Zoom.
7:30 p.m. – 9:30 pm
Free for anyone to attend.
See http://www.edmontonrasc.com for more details.
December 13-14 Geminid meteor shower peaks! Moon light interferes this year.
December 21 Winter solstice occurs at precisely 2:21 a.m. MST
December 22 Ursid meteor shower peaks. Minor meteor shower.
December 25 Mercury at its greatest western elongation of 22 degrees from the Sun