December 2015

To see a video of this information, go to my YouTube Channel

The holidays should be merry and bright for astronomers!  The morning sky provides us with Jupiter, Mars, and Venus visible with a comet nearby and the Moon riding by early in the month.  Additionally, the Geminid Meteor Shower will be extra showery this year, the Moon will occult Venus, and the longest night of the year all occur this December. 

PLANETS...well, the ones visible with your naked eye

Planets you can see around Sunset – Mercury after the 16th (SW)

Planets you can see throughout the night – Jupiter (E)

Planets you can see in the Morning – Venus (SE), Mars (S), Jupiter (S), Saturn after the 15th (SE)

Mercury – Starting on the 16th, you should be able to see it in the SW after sunset with binoculars, and by the end of the month it’ll be visible for 1.5 hours after sunset.   

Venus, Mars, & Jupiter Look toward the East after 4:30am and you’ll find all three planets. Venus will be the brightest object, lowest in the sky, with Mars about 15˚ above and Jupiter 20˚ above that in the beginning of the month.  Throughout December, they’ll spread apart, with Venus and Jupiter about 70˚ apart by the new year. Jupiter will be up in the east 12:30am in the beginning of the month and 10:30pm at the end of the month.  Mars rises around 2am, Venus around 4:30am.

Saturn – Saturn will start being visible before sunrise in the SE, below and to the left of Venus starting on the 15th of the month.  It will get higher and closer to Venus each day, until it’s only 10˚ below Venus on the 31st.


Comet Catalina – This comet has been making some waves in the Northern Hemisphere.  Sky & Telescope has a guide to observing it.  It’s not likely going to be a Halley’s Comet, but it could reach naked eye visibility, but as comet hunter David Levy says, comets are like cats: They both have tails, and they do precisely what they want.  So, really we don’t know how bright it will get.

                  It’s a morning comet, so you’ll have to get up early and look SE. On the 1st, it’s about a fist-width down and to the left of Venus.  It gets very close to Venus (and the Moon) on the 7th, being only 4˚ directly to the left of Venus. From there, it will consistently move higher and higher straight above Venus, and around the holidays it will be near Arcturus (the brightest star in Bootes) about 45˚ above Venus and 45˚ left of the Moon and Jupiter.

Last Quarter Moon – 3rd (Visible from midnight into the morning) 

3rd – 7thClose Encounter – Moon, Jupiter, Mars, Venus, Comet Catalina – Look toward the East in the mornings and find the Moon.  On the 3rd, the Moon will be above Jupiter, with Mars and Venus below and closer to the horizon.  The next morning, the Moon will have moved to be only 3˚ below Jupiter. On the 5th the Moon will be between Jupiter and Mars (closer to Mars), and on the 6th the Moon will be just below Mars.  Finally, on the 7th the Moon will be just 2˚above Venus, with Comet Catalina 4˚ to the left of Venus.

7th – OCCULTATION – Venus by the Moon – Find the VERY thin Moon only about 45˚ west of the Sun, or find bright Venus as a dim star in the sky in the same spot. The Moon will pass directly in front of, and block, Venus.  When? Sky & Telescope says that in Washington D.C. the disappearance will be at 12:39pm and Venus will reappear at 1:51pm.  Your time will vary based on location.  

New Moon – 11th (darkest skies)

13th, 14thGeminid Meteor Shower – It’s a good year for the Geminids, which will produce 120 meteors per hour this year, though you’ll probably see a little bit less, depending on your light pollution levels.  Best time is after midnight

Some advice for watching:

    Find a dark location and lie down in a reclining chair or swimming pool floaty

    Look toward Gemini (in the East). That is where the radiant is - where the meteors will appear to be coming from.  Keep a wide eye and try to take in the whole sky, instead of staring at one spot or through binoculars or a telescope.

    Dress in multiple layers and bring hot chocolate

    Check the weather to see if the skies will be clear ( has a good map here)

    Adapt your eyes to the dark by staying away from light sources or using a red light if you need to look at a star chart or not trip over something. 

    You could contribute to science and its accuracy in predicting meteor showers by doing an easy scientific meteor count.  Details here:

First Quarter Moon – 18th (Visible until midnight)

21stWinter Solstice - The longest night and shortest day of the year for the Northern Hemisphere. More info here:

Full Moon – 25th (Visible all night)           

31stClose Encounter – Moon & Jupiter – On the morning of the 31st (after midnight on the 30th), look East for the Gibbous Moon 5˚ up and to the right of Jupiter. By morning they will be higher in the sky and closer.

CONSTELLATIONS... (see sky map link at the bottom for a Star Map for this month – or ask Mr. Webb)    Look straight up and you'll see...

After Sunset (sunset is around 5:00pm) – Pegasus, Andromeda - Extra Challenge!  Using your naked eye (dark-adapted and in a dark area) or binoculars under normal conditions and a star chart, try finding our neighboring Andromeda Galaxy.  It’ll be a faint, but bigger, fuzzy in the constellation Andromeda.

Between Sunset and Midnight – Perseus, Andromeda, Cassiopeia

Midnight – Auriga, Taurus, Gemini

Early Morning – Ursa Major’s legs, Leo Minor


Fall Constellations: Andromeda, Pegasus

If you can find the Summer Triangle and Delphinus in the West, about 40˚ to the East (leftish – pretty much straight above you) will be the Great Square of the fall constellation Pegasus.  Perhaps you’ll even see the two curves of Andromeda off of one side, with the Andromeda Galaxy as a small, faint fuzzy nearby (you’ll need dark skies to see it).  A sky map will help you tremendously in finding these. 

Winter constellations:  Orion is easy to spot as he is rising in the East around 7:30pm.  You can use Orion to find many other winter constellations.

Using Orion:  Find Orion by looking for the three stars in a row that make up Orion’s belt in the East around 7:30pm.  If you draw a line from the left (bottom) star to the right (top) star and keep going right about 20 degrees (about 2 fists at arm’s length) until you reach another very bright star, you will have reached the star Aldebaron in Taurus (the V).  Follow that line a little more (about another fist) and you’ll find the Pleiades.

Draw a line from the right (top) star in Orion’s belt to the left (bottom) star, and keep going left about 20 degrees (2 fists again), you’ll come to the brightest star in the sky – Sirius – part of Canis Major.

Above these three constellations are Gemini and Auriga.  The brightest stars in each of these constellations form a circle in the sky.  Going clockwise - Aldebaron (Taurus) – Rigel (Orion – bottom right foot) – Sirius (Canis Major) – Procyon (Canis Minor) – Castor & Pollux (Gemini) – Capella (Auriga).  It makes for great stargazing in the winter sky.

Use a sky map from to help you out.


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