December 1, 2016

The Night Sky:
December supermoon will dim the Geminids

By GERRY LEBING


The evening of Tuesday, Dec. 13, will feature the last supermoon 2016. It will not be quite as spectacular as November’s full moon, but it will still be pretty bright.  December’s full moon will have a visual magnitude of -12.5! That’s bright enough to throw shadows.

Unfortunately, the supermoon will also make it super hard to get a look at the Geminids meteor shower. The Geminids peak on the morning of Dec. 14.   Normally, an observer might see 120 shooting stars per hour, but the full moon will probably reduce this year’s visible meteors to about 10 to 20 per hour.

The supermoon will not interfere with the Ursid meteor shower.  It will peak in the early morning hours of Dec. 22 and feature about 10 meteors per hour.  The shower appears to originate from Ursa Minor.  Ursa Minor -- the Little Bear -- contains the Little Dipper and the first star in the handle of the Little Dipper is Polaris, the North Star, so it’s pretty easy to get a handle on where to look for this meteor shower.

Another nice feature of the Ursid shower is it ends on Dec. 23 so it won’t interfere with any children (or parents) who want to keep an open eye out for flying sleighs on the 25th!

December will start with Mercury, Venus, and Mars visible in the evening skies.  Mercury will be closest to the western horizon and disappear from view shortly after dusk.  Venus will start the month fairly high and bright in the southwest sky with Mars appearing higher and more to the south-southwest.   Neptune and Uranus are also present in the night skies, but you need a telescope to get a good view of them.

Jupiter will be visible in the pre-dawn skies near the eastern horizon.  It rises in the east about 2:40 a.m. on Dec. 1.

The bright star Capella will be visible slightly above the northeast horizon as soon as the skies begin to darken.  Capella is the sixth brightest star in the night skies.  Capella is a Latin word that means “the little she-goat.”  If you look slightly south of Capella, you should be able to spot a group of three fainter stars.  They are called the “kids.”

NOVEMBER HIGHLIGHTS

The biggest sight in November’s night sky was the supermoon of November 14.  This was the closest the full moon has been to the Earth since 1948.  We will not see another comparable super moon until 2034. (Photograph courtesy of NASA.gov.)

The clear skies of November also gave me a unique astrophotography opportunity.  I was able to get a decent image of the Bubble Nebula, below.  This faint emission nebula is 1,400 light years away and has a visual magnitude of +11.00. It is located in the constellation Cassiopeia.

The image is the result of stacking 100 frames.  Each frame has a 25 second exposure time.



I also got a fairly good shot of the Pacman Nebula.  For those of us who were around in the '80s, the reasoning behind the name is pretty obvious.  If you’re too young to remember the video game, you might want to try Googling “Pac Man.”  The Pacman Nebula is 4,000 light years away and has a visual magnitude of +7.4.   Like the Bubble Nebula, it is found in the constellation, Cassiopeia.



Since I have been focusing on Cassiopeia, here is another object from that area of the sky, the Owl Cluster.

The Owl cluster has a visual magnitude of +6.4.  It’s 7.9 thousand light years away.






MOON PHASES
First Quarter: Dec. 7
Full moon: Dec. 13
Last Quarter: Dec. 20
New moon: Dec. 29

(Gerry Lebing is a retired computer scientist with the U.S. Geological Survey in Washington, D.C.  He has visited Hatteras Island since the mid-1970s. He and his wife, Karen, have owned property here for several years and moved to their home in Waves full-time in 2013.  Astronomy is a subject that Gerry says he has always been interested in and one that he pursues seriously -- he's built an small observatory next to his house. You can send him questions about the night sky through e-mail, [email protected]g.)


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