December 2011 Guide to the Five Visible Planets

Whoa! I just realized how long it’s been since our last post…Yikes!

I feel like I should make it up to you with a superinformative post.

I love the evening sky. The stars have always fascinated me! In fact, my parents bought me my first telescope when I was in 3rd grade. My dad spent a lot of time explaining to me the moon phases, about the planets and the constellations and of course, he made sure that we never missed an eclipse.

This month you too may be able to spot all five visible planets – Mercury, Venus, Mars, Jupiter and Saturn.  Hey…we may even both be looking up at the sparkling night sky at the same time 🙂

Jupiter's Great Red Spot, seen by Voyager spacecraft

Jupiter’s Great Red Spot, seen by Voyager spacecraft

All five visible planets beautify the December 2011 night sky

In their outward order from the sun, the five visible planets are Mercury, Venus, Mars, Jupiter and Saturn. By visible planet, we mean any planet that can be viewed without an optical aid and that was known to our ancestors since time immemorial. All of them except for Mercury can be seen for at least part of the night all through December 2011. In the second half of December, you can catch Mercury low in the east to southeast an hour (or more) before sunrise, or as darkness begins to give way to dawn.

Evening planets in December 2011: Venus and Jupiter

Venus and Jupiter – the sky’s two most brilliant planets – pop out first thing at evening dusk. Given clear skies, you simply can’t miss these dazzling worlds. Shining much more brilliantly than any star, Venus and Jupiter rank as the third-brightest and fourth-brightest celestial bodies to light up the heavens, respectively, after the sun and moon.

Venus blazes like a lighthouse in the southwest sky at dusk and early evening. But be sure to catch Venus soon after the sun goes down. At mid-northern latitudes, this world follows the sun beneath the horizon less than two hours after sundown in early December. By the end of the month, Venus stays out for over two and one-half hours after sunset. In January 2012, watch for Venus to climb up higher into the evening sky and to stay out longer after dark.

Use the moon to verify that you’ve found Venus in late December, as the thin lunar crescent pairs up with Venus on the evenings of December 26 and 27.

The moon and Jupiter as seen on Sunday evening, December 4.

Jupiter shines from nightfall until the wee hours of the morning all though December. Because Venus – the sky’s brightest planet – sets in the southwest at early evening, that leaves Jupiter to lord over the late night sky all through December. Watch for Jupiter to move westward and upward throughout the early evening hours. Jupiter transits – that is, reaches its high point in the sky – at roughly 9 p.m. in early December and 7 p.m. by the month’s end.

After soaring to its highest point for the night, Jupiter then descends into the western half of the sky. Look for Jupiter to set in the west earlier each morning as December approaches January. Jupiter sets in the west around 4 a.m. in early December, and 2 a.m. by the end of the month. As Jupiter sets in the west, look for Saturn to rise in the east.

Jupiter and its moons as seen on August 15, 2009. From left to right, these moons are Europa, Ganymede, Io and Callisto.

Use the moon to verify that you’ve found Jupiter early in December, as the waxing gibbous moon passes close to Jupiter on the nights of December 4, 5 and 6.

Even on a moonlit night, it’s pretty easy to see Jupiter’s four largest moons with a backyard telescope. In their outward order from Jupiter, these moons are Io, Europa, Ganymede and Callisto. However, the position of Jupiter’s moons – as seen from Earth – varies from night to night. Sometimes, a moon may be “missing” because it’s in front of or behind Jupiter. If you want to know which moon is which at a certain date and time, check out this handy almanac.

Jupiter photo credit: Velo Steve

Morning planets in December 2011: Mars, Saturn and Mercury

Mars could be considered an evening planet because it rises over the eastern horizon around 11 p.m. to midnight in early December and around 10 to 11 p.m. by the month’s end. Before dawn is really the best time to see Mars, however, for that’s when the red planet appears highest in the sky. Mars transits – that is, reaches its highest point in the sky – around 6 a.m. in early December and 5 a.m. in late December.

Mars resides in front of the constellation Leo, somewhat close to Leo’s brightest star Regulus. You can distinguish Mars from Regulus by color. Mars exhibits a ruddy complexion, whereas Regulus is blue-white in color. Binoculars help to highlight the colors of these two celestial gems!

If you’re not a night owl, look for the moon and Mars in the southern sky dawn Saturday, December 17.

If you have difficulty locating moderately bright Mars, let the moon assist you in mid-December. The waning moon will be shining close to Mars from late night till dawn on the nights of December 15/16 and 16/17.

Moon by Regulus, approaching Mars on December 15

Nice pairing of Mars and moon after midnight December 17

Saturn rises at around 3:30 to 4:30 a.m. in early December (at mid-northern latitudes). By the end of the month, Saturn rises around 1 to 2 a.m. If you have a level horizon east and west, you can see Jupiter sitting low in the west as Saturn is rising in the east. Saturn appears highest in the sky just before dawn.

Saturn resides in front of the constellation Virgo, fairly close to Virgo’s brightest star, Spica. Be sure to see the beautiful pairing of the waning crescent moon with Saturn and Spica before dawn on Monday, December 19 and Tuesday, December 20.

Rising times of the morning planets into your sky

Look for the waning crescent moon and Mercury before sunrise on Thursday, December 22.

Mercury, the solar system’s innermost planet, makes an exceptionally good appearance in the morning sky from about December 14 to 27. Look low in the east to southeast sky about one to one and one-half hours before sunrise. Let the moon be your guide to Mercury on the mornings of Thursday, December 22 and Friday, December 23.

Bottom line: All five visible planets can be seen from both the Northern and Southern Hemispheres in December 2011. Venus is visible from dusk until early evening. Jupiter shines from dusk until the wee hours of the morning. Mars appears in the sky from around midnight until dawn. Two planets – Venus and Jupiter – conspicuously stage themselves in the December 2011 evening sky, while Mars and Saturn more modestly display themselves in the predawn sky. Mercury, the shyest of the five visible planets, nonetheless makes a noteworthy appearance in the second half of December 2011, shining in the east to southeast sky just as darkness gives way to dawn.


One thought on “December 2011 Guide to the Five Visible Planets

  1. Your post brought back memories of all the astronomy magazines that use to accumulate in your bedroom. I am sure Dad will show me the planets that you and he are so fond of discovering, and I’m pleased to be informed about. Thanks for the information and the memories!

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