The Sky This Month – December 2016

Meteors from the Geminid meteor shower (credit: Asim Patel)

Meteors from the Geminid meteor shower (credit: Asim Patel)

It’s an excellent month for stargazers, so I encourage you to take some time out of your busy holiday preparations to enjoy the night sky. There are two respectable meteor showers, and the Moon passes close to five major planets during the month. Brilliant Venus dominates the western sky after sunset, while Jupiter outshines every star as it continues to brighten in the eastern sky before sunrise. And on the last day of 2016, Neptune comes within 0.1º of the planet Mars, the closest approach of these two planets in more than 700 years! Here’s what to see in the night sky this month…

A quick reminder to order your Year in Space Calendars for 2017. Winner of the NBC News Digital Website’s “Science Geek Gift of the Year” award, this large and colorful calendar is packed with facts and images related to space flight, stargazing, and planetary exploration. This year it’s available directly from Amazon (and to U.S. residents only). Here’s the link for the wall calendar. And there’s the link for the desk calendar.

The 'Year in Space' 2017 wall calendar by YearinSpace.com

The ‘Year in Space’ 2017 wall calendar by YearinSpace.com

3 December. That bright star near the Moon in the western sky after sunset? It is the planet Venus, the brightest object in the night sky except for the Moon. Venus dominates this part of the sky as the “evening star” for the next few months. Here’s a brief guide to help you see this bright planet during this apparition.

5 Dec. The Moon continues its planetary rendezvous. Tonight it’s just a couple of finger widths from the red-orange disk of the planet Mars. Mars itself is fading as it sinks closer to the Sun each night. The planet presents little detail in a telescope but still has an unmistakable color.

6 Dec. Tonight the Moon passes less than 1º (about the width of your little finger held at arm’s length) north of the planet Neptune.

7 Dec. First Quarter Moon, 9:03 Universal Time.

9 Dec. Yes, the Moon once again brushes past a planet, in this case, Uranus, which is about 3° north of the gibbous Moon.

10 Dec. Mercury reaches greatest eastern elongation and lies 21° east of the Sun. It’s low on the western horizon after sunset in the northern and southern hemispheres and lies in a long line with Venus and Mars.

From lower right to upper left, the planets Mercury, Venus, Mars, and Neptune (not visible to the naked eye) in the southwestern sky after sunset on Dec. 10, 2016.

From lower right to upper left, the planets Mercury, Venus, Mars, and Neptune (not visible to the naked eye) in the southwestern sky after sunset on Dec. 10, 2016.

13 Dec. The Geminid meteor shower peaks tonight and early tomorrow morning. This meteor shower, one of the best of the year, shows some 100-150 meteors per hour in dark sky. The Full Moon gets in the way of the faintest meteors this year, but unlike most meteor showers, the Geminids are active earlier in the evening before the Moon dominates the sky. The Geminid meteors are slow moving, bright, and often colorful.

14 Dec. Full Moon, 00:06 UTC

21 Dec. Last Quarter Moon, 00:56 UTC

The Moon and Jupiter in the southeastern sky before sunrise on Dec. 22, 2016.

The Moon and Jupiter in the southeastern sky before sunrise on Dec. 22, 2016.

21 Dec. December Solstice, 10:44 UTC. The Sun reaches its most southerly point on the ecliptic. This is the first day of winter in the northern hemisphere and the first day of summer in the southern hemisphere.

22 Dec. The Ursid meteor shower peaks. The Moon gets out of the way for the Ursid meteor shower this year. You might see up to 10 meteors per hour as part of this shower. The Ursids trace their path back to a point near the star Kochab in the constellation Ursa Minor.

22 Dec. Look for the waning crescent Moon near the brilliant planet Jupiter in the eastern sky before sunrise. Jupiter is brighter than any star and grows brighter and larger each week. Look with binoculars for its four large moons, or for its two most prominent belts in a small telescope.

Mars and Neptune come within 0.1 degrees of each other on Dec. 31, 2016. The planets are in the western or southwestern sky after sunset on this day.

Mars and Neptune come within 0.1 degrees of each other on Dec. 31, 2016. The planets are in the western or southwestern sky after sunset on this day.

29 Dec. New Moon, 06:53 UTC

31 Dec. Neptune and Mars come as close as 0.1º (6 arcminutes) of each other, their closest approach since the year 1305.  Observers in Hawaii and Alaska see the closest approach, while observers across much of North America see a separation of about 10 arcminutes, still an impressive sight. You can see both planets in binoculars, but a telescope at high magnification will give you a much better view. The two planets are found in the western sky after sunset.

(All sky simulations created with SkyX Serious Astronomer edition by Software Bisque.)

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