The moon begins the month just past new phase, so is visible low in the west, but challenging. Saturn will likely be lost in the sun’s glare, but Mercury and Venus will be in the same part of the moon’s sky at sunset.
By Dec. 6, the moon will have moved over to Neptune’s part of the sky, occulting that distant planet for viewers in most of Central and North America, plus parts of Western Europe. Dec. 13, another occultation occurs with the bright star Aldebaran, for the same viewing area as the previous one.
The moon is full the following evening, Dec. 14. Regulus is a close companion Dec. 19, an occultation for the extreme south of Australia. Jupiter is within two degrees of the waning moon on the early morning of Dec. 22 in the eastern sky.
Mercury, Venus, and the moon make a nice trio as the sun goes down in the west. The speedy Mercury rises higher each night up to Dec. 15, then begins the descent to pass in front of the sun once again at month end.
Venus is at mid-height in the western sky as December begins, with the moon and Mercury close by in the evening twilight, and Mars a bit further east. The bright planet Venus continues to get higher as each day passes. The dim sliver of the moon slides by on the nights of Dec. 2 and 3.
Mars is in the western sky to the east of Venus as December begins, joined by the moon on the night of Dec. 4. The ruddy planet moves from the constellation Capricornus into Aquarius in the middle of the month.
Jupiter rises in the east a couple of hours before the sun. Watch for the nearby moon Dec. 22.
Saturn is very much in the sun’s glare and remains so throughout the month.
Uranus rises in the east at sunset and crosses the sky in retrograde motion through the night. The moon glides under the blue-green Uranus Dec. 9.
Neptune rises in the east in early afternoon, so becomes visible only after sunset, almost due south. A telescope is a must to see the distant green planet.
The Geminid meteors peak Dec. 14 and the Ursids peak Dec. 22. These names derive from the apparent “radiant” – where the meteors appear to originate.
The winter solstice occurs Dec. 21.
— James Edgar has had an interest in the night sky all his life. He joined The Royal Astronomical Society of Canada in 2000 and is now the Society’s president, assistant editor and a contributor to the renowned Observer’s Handbook, and production manager of the bi-monthly RASC Journal. He was given the RASC Service Award at the 2012 General Assembly in Edmonton.
