Monday, December 5, 2011

Astronomy: The December Night Sky

Hope everyone has a great and safe holiday season. Here are some objects for the unaided eye for the month of December. All of these objects, although small, should be visible without the help of binoculars or a telescope, so long as you have clear dark skies.

Light pollution is a killer for seeing these objects with your naked eye. To find out how dark your location is, use the Google Map Overlay of light pollution. If you are in a blue, gray or black area then you should have dark enough skies. You may still be able to see some of these objects in a green location. If you aren’t in a dark sky location you may still be able to see these objects with a pair of binoculars or telescope. Snow will add more light pollution due to light reflecting off of it.

You can find help locating the night sky objects listed below by using one of the free sky charts at (scroll down to Northern Hemisphere Edition and click on the PDF for December 2011). The map shows what is in the sky in December at 8 pm for early December; 7 pm for late December.

If you are not familiar with what you see in the night sky, this is a great opportunity to step outside, look up, and begin learning the constellations. The sky is beautiful and filled with many treasures just waiting for you to discover them. Once you have looked for these objects go through the list again if you have a pair of binoculars handy, the views get better!

New note: Measuring Degrees with your hands, proportionally works for people of all ages. Extend your arm out and do the following.
Width of your pinky finger is 1°
Width of your ring, middle, and index finger equals 5°
Width of your fist equals 10°
Width from tip to tip of index finger and pinky finger stretched out equals 15°
Width from tip to tip of your thumb and pinky finger stretched out equals 25°

Meteor Showers
Geminid meteor shower peaks this month on December 14th with a possibility of 120 meteors per hour. Again another meteor shower that will be hard to catch due to an 89% full Waning Gibbous Moon. I would still suggest giving this meteor shower a look because even the brightest ones can’t be outshined by the Moon. Best viewing time for the Geminid’s is early morning on the 14th with the radiant being between the stars Castor and Pollux (the two brightest) in the constellation Gemini. The meteors in this shower often produce fire balls entering Earth at 21.75 miles per second generating a multi-colored display of whites, yellows, and a hint of blues.

The Moon
December 5th Jupiter will be 9° to the left of the Moon.

December 6th Jupiter will be 6° below the Moon.

December 10th is the full Moon also known as the Christmas Moon, Bitter Moon, and Snow Moon.

December 17th is the Last Quarter Moon which will be visible from Midnight into the morning. Also on this night you can find Mars 8° to the left of the Moon.

December 19th Saturn will be 13° down and left of the crescent Moon.

December 20th Saturn will be 7° up and to the left of the crescent Moon.

December 22nd Mercury will be 9° to the left of the very thin crescent Moon in the morning.

December 23rd Mercury will be 6° above the very thin crescent Moon in the early morning.

December 24th New Moon also referred to as No Moon. Best night to star gaze!

December 26th Venus will be 7° to the right of the very thin crescent Moon.

December 27th Venus will be 7° above the very thin crescent Moon.

On the morning of December 23rd Mercury reaches it’s greatest elongation meaning it will be the highest in the sky that it will get for quite a while. If you look East Southeast in the early morning before the sun rises you’ll see Mercury 9° to the left of the Moon on the 22nd, and 6° above the Moon on the morning of the 23rd although you may have trouble seeing the Moon as it will be a very thin crescent Moon.

Looking Southwest after sunset you’ll see Venus, the brightest object about 15° above the horizon. Venus will set at around 6pm. On the 26th and the 27th Venus will be close to the Moon.

Rising around 11pm in the East is Mars reaching 45° in the sky by sunrise. Mars can be found within the constellation of Leo. To the naked eye it will look like a star with a reddish hue, slightly brighter than the brightest star in Leo – Regulus. Mars will be above the 3rd Quarter Moon on the 17th.

Jupiter rises before sunset and is in the South East after the sun finally sets. Jupiter sets around 3am throughout the month of December. Jupiter will be close to the Moon on the nights of the 5th and 6th. If you happen to have a pair of binoculars you can view the Moons of Jupiter – Io, Europa, Ganymede, and Callisto – as they orbit around the giant gas planet as the pattern of the Moons change daily.

Saturn still comes up early in the morning before sunrise in the Southeast and will reach up to 30° above the horizon this month. Look for Saturn on the morning of the 20th to see it 7° above a thin crescent Moon.

Straight overhead will be the constellation Pegasus. This constellation is easy to spot due to there being 4 stars that form the Great Square of Pegasus with a seemingly empty area inside of it.

To the South of Pegasus is the constellation Pisces. Easily found following the right side of the square of Pegasus south until you reach the keystone of Pisces.

To the East of the square of Pegasus, attached to it in most drawings of the constellations, is the constellation Andromeda. If you find the bright star Mirach and follow the chain of stars to the North it will bring you to the Andromeda galaxy in clear dark skies.

The constellation Triangulum is to the South of Andromeda. Made up of only 3 stars forming a triangle shape.

A great grouping of stars in the constellation of Taurus the Bull. Looking at it has always reminded me of a smaller version of the little dipper. In dark locations you can see anywhere from 5-7 and possibly a few more stars in this grouping. It has also been called the seven sisters and is actually a Messier object, number 45. These are very hot blue and extremely luminous stars that have formed within the last 100 million years. This grouping of stars has quite a bit of history in mythology. It rises about 45 minutes earlier than Orion in the East.

The Andromeda Galaxy cataloged as M31 is visible to the naked eye in the northeast. The Andromeda Galaxy is the closest galaxy to the Milky Way lying about 2.5 million light-years away. If in a dark enough location the light produced by this galaxy is roughly the diameter of 5 moons in our sky.

The Double Cluster, cataloged as NGC 869 and NGC 884 is a beautiful cluster that shows quite a group of stars with the naked eye. M34, which you may need to wait until around 11pm for it to be high enough to see is nearly a moon-diameter wide and is a fairly easy to see open cluster.
Look for a grouping of stars around the brightest star in Perseus, Mirphak.

North America Nebula (NGC7000) – The unaided eye sees only a wedge-shaped star-cloud which may be quite dim, or not visible at all. In dark skies it should pop out a bit. Located near the star Deneb. M39 an open cluster patch of stars northeast of the star Deneb. The Northern Coalsack spans across the sky between the stars Deneb, Sadir, and Gienah in the northeastern portion of Cygnus. If you don’t know which stars of Sadir and Gienah just find Deneb with the map and look to the east northeast.

Ursa Major

Very low on the horizon at sunset and not rising back into the sky until after midnight. Mizar and Alcor is a double star in the handle of the Big Dipper. Was once used as a test of good eyesight before glasses. Mizar resolves into a beautiful blue-white and greenish white binary (double star system). They are labeled on the map I linked to above.

Photo Above: Star trails taken by Michael Rector.

Photo Below: The radiant of the Geminid Meteor Shower. The red dot shows the radiant of the meteors and the position of the Moon at 3:30am on the morning of the Peak. Screen grab from the astronomy freeware Stellarium.

Michael Rector is an amateur astronomer with his own blog, Adirondack Astronomy.

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Although he now lives in Clinton County, amateur astronomer Michael Rector has fond memories of spending time at Great Sacandaga and West Canada Lake where the skies are dark and the Milky Way is bright.

Michael writes about astronomy on his own blog Adirondack Astronomy and is interested in getting together with other star-gazers around the region. If you are interested in getting together for an occasional star party feel free to contact him at


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