Mercury is a morning object for most of December

Saskatchewan Skies

James Edgar

The moon begins this month nearing first quarter, meaning slightly more than seven days past new. Dec. 8, Uranus is five degrees north of the moon; by Dec. 11, the moon is full. The next day, Dec. 12, the stars of M35 provide the backdrop; M35 is a large open cluster in Gemini. Dec. 15, the Beehive Cluster sets the scene in the stars of Cancer, the Crab. Dec. 22 sees Mars within four degrees of the waning crescent moon, and the new moon Dec. 26 brings a solar eclipse. Unfortunately, for us, the event is only visible from the Eastern Hemisphere.

Friday, Dec. 27, brings Saturn and Pluto up close, 1.2 and 0.6 degrees apart, respectively. The Pluto observation would be a challenge to see, and even more difficult to see the occultation that day, since it's only visible from the Antarctic or the southern tips of the continents. Another difficult occultation is when Venus slides behind the moon, but only visible from Antarctica or the southern tip of South America.

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Mercury is a morning object for most of December, gradually sliding behind the sun near month end. The ecliptic is high in the east before sunrise, so viewing is favourable for Northern Hemisphere observers.

Venus is on theopposite side of the sun from Mercury, so is a western evening object, gradually getting higher and higher in the sky. Venus passes two degrees south of Saturn on the evening of Dec. 10. The moon visits the bright planet Dec. 28, as noted above, only three days past new phase, so just a thin sliver.

Mars is among the stars of Libra in the eastern morning sky, but still a dim red spot as it is so far away, nearly 2.5 times the distance we are from the sun. The moon passes by Dec. 22.

Jupiter is increasingly difficult to see in the southwestern evening sky, reaching conjunction with the sun Dec. 27.

Saturn is also deep in the southwestern sky, increasingly difficult to spot as the month progresses.

Uranus is visible in the southwest among the stars of Aries, as it sets around 4 a.m., south of the Pleiades, the Seven Sisters.

Neptune is visible during the evening, setting near midnight.

The Geminid meteor shower peaks Dec. 14.

James Edgar has had an interest in the night sky all his life. He joined The Royal Astronomical Society of Canada in 2000, was national president for two terms, is now the editor of the renowned Observer's Handbook, and production manager of the bi-monthly RASC Journal. The IAU named asteroid 1995 XC5 "(22421) Jamesedgar" in his honour.




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