Only one planet is easily visible at dusk and nightfall throughout December 2013: Venus. It is shining at its brightest now; you can’t miss it. Venus! It’s the beautiful evening star. Plus Jupiter can be seen in the evening sky. In early December, look for the giant planet to rise in the east about three hours after sunset, or at about the time that Venus sets. By late December, Jupiter will be up by dusk or nightfall, or roughly an hour before Venus sets in the west. If you have an unobstructed horizon, you should be able to see Venus and Jupiter shining pretty much opposite of each other at early evening, starting around the second week of December. They are the sky’s two brightest planets, and they’ll be like bright bookends, briefly, enclosing the evening sky.
Meanwhile, if you’re a night owl or early riser, watch for Mars and Saturn and Mercury in the morning sky. Mars shines in front of the Constellation Virgo the Maiden, rising in the east about one hour after the midnight hour in early December, and coming up around midnight on New Year’s Eve. Mars reaches its highest point for the night at or near dawn all through December. At mid-northern latitudes, Saturn rises about two hours before the sun in early December, and nearly four hours before sunrise by late December. You might catch Mercury before sunrise in early December, but this world quickly sinks into the glare of sunrise each day thereafter, to pass from the morning to evening sky by the month’s end.
Follow the links below to learn more about planets and special sky events in December 2013.
Special events coming up:
Planets in evening sky in December
Planets in morning sky in December
Venus after sunset. Venus beams mightily in the west at dusk, as seen from across the Earth. Venus is always a dazzling object, as seen from around the globe. This month is special for Venus, though, in terms of brightness. The planet will be at its brightest as the evening star at the end of the first week of December. People used to call this Venus’ greatest brilliancy. Now you often hear the less romantic term greatest illuminated extent. Either way, Venus is at its brightest around December 6.
Venus sets about three hours after sunset at mid-northern latitudes in early December, and approximately one and one-half hours after the sun by the month’s end.
Why the difference? Venus is about to pass more or less between the Earth and sun (inferior conjunction). It’ll remain in the evening sky throughout December, but will pass into the morning sky in January 2014.
You usually need a telescope to observe the phases of Venus. Toward the latter part of December 2013, however, you might be able to see the thin crescent Venus with binoculars – or even the unaided eye. Why is Venus a crescent now? Remember, it’ll soon pass between us and the sun. So its illuminated half – its day side – is facing mostly away from us now.
Whenever you see Venus in the evening sky, it is always approaching Earth and its phase is continually waning (getting thinner). This month, Venus’ disk starts out about 30% illuminated in sunshine and ends the month about 5% illuminated. Whenever you see a quarter-lit Venus in the telescope, as you will around December 6, you know this world is at or near its greatest illuminated extent. At this juncture, the illuminated portion of Venus’ disk covers the most square area of sky, with this dazzling world shining most brightly in its present apparition as the evening star.
This month will be about as good as it gets for observing the phases of Venus through a telescope. The crispest views come right after sunset. As dusk deepens into night, Venus sinks closer to the murk of the horizon, and moreover, Venus becomes too glary for a delectable eyeful of its banana-shaped crescent.
The sooner you catch Venus after sunset, the better!
Saturn in predawn and dawn sky. At mid-northern latitudes, Saturn rises about two hours before the sun in early December and about four hours before sunrise by the month’s end. This golden-colored world shines in front of the constellation Libra the Scales.
Earth flew between the sun and Saturn last on April 28, 2013, so Saturn’s time of greatest prominence in our sky is long past for this year. In fact, if you want to see Saturn at its best, you might start looking forward to next year. Saturn fell into the sunset glare in mid-October 2013 and recently reappeared in the morning sky in the latter part of November 2013. Saturn will be at its best in May 2014.
Binoculars won’t reveal Saturn’s gorgeous rings, but a small telescope will. This month, your best chance of viewing Saturn’s rings will be toward the end of the month, when Saturn rises several hours before dawn. But December will present Saturn much higher in the predawn sky than in November 2013. Saturn’s rings are inclined by more than 21o from edge-on in December 2013, showing us their north face. Some four years from now, the rings will open most widely in October 2017, displaying a maximum inclination of 27o. As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27o by May 2032.
Mercury before sunrise early December. Mercury is at the tail end of a fine morning apparition for the Northern Hemisphere, centered on November 18, 2013. So you might catch Mercury before sunrise in early December. Try using the slender waning crescent moon to spot Mercury, Saturn and Comet ISON before sunrise December 1. Mercury will pass into the evening sky in late December 2013, but probably won’t become visible in the western evening twilight until the second half of January 2014.
Jupiter: early evening, predawn, dawn. As December begins, our solar system’s largest planet, Jupiter, is easy to see starting at early-to-mid evening, and this brilliant beauty of a planet lights up the nighttime all the way to dawn. It is rising around 7 to 8 p.m. in early December. By the end of the month, Jupiter is up by dusk or nightfall (approximately 6 p.m.).
There are two bright stars near Jupiter now. They’re noticeable for being both bright and close together on our sky’s dome. They are Castor and Pollux in the constellation Gemini.
Jupiter at nightfall means we are getting closer to the giant planet’s yearly opposition, which will happen in early January 2014.
In other words, Jupiter is the planet to watch – to replace Venus as the bright beacon in the evening sky in January 2014! It’s now nearly at its best. Keep your eye on Jupiter, as this brilliant world will become more and more visible in the evening sky. In late December 2013/early January 2014, Jupiter will shine from dusk until dawn.
Mars: predawn, dawn. Mars becomes a easier to spot before sunrise in December, as it climbs a higher into the predawn sky and brightens all month long. Keep in mind that Jupiter shines many times more brilliantly than Mars does. At or near dawn, Jupiter sits low in the west whereas Mars shines at or near its highest point in the sky. Mars transits -reaches its high point for the night – around 7 a.m. in early December and 6 a.m. by around New Year’s Day.
Use the last quarter/waning crescent moon to find Mars between midnight and dawn on the mornings of December 25 and December 26.
What do we mean by visible planet? By visible planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five visible planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets are visible in our sky because their disks reflect sunlight, and these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. They tend to be bright! You can spot them, and come to know them as faithful friends, if you try.
Bottom line: In December 2013, two of the five visible planets – Venus and Jupiter – will be easily visible in the evening sky. Mars comes up after midnight, and Saturn is up before dawn. Mercury may be visible in early December, but sinks into the glare of sunrise shortly thereafter.