Venus has been hovering low in the west a few hours after sunset since it returned to the evening sky a few months ago. In December, Venus-set increases from 3 hours after sunset in the beginning of the month until nearly 4 hours after sunset by New Year’s Day.
In addition to Venus, Mercury remains in the evening sky during the first two weeks of December. One-half hour after sunset, look for Mercury far to the lower right of Venus. During the first couple days of the month, a crescent moon will join Venus and Mercury in the evening sky.
As you are looking at these two planets in the southwest sky, scan your eyes eastward and spot reddish Mars. If you have been following Mars throughout the summer and fall, you will now notice that Mars is much fainter than it was last summer. However, even though its brightness has diminished, it still outshines the background stars in the vicinity of the red planet.
Keep an eye on both Venus and Mars throughout the winter months. Mars is still quickly moving eastward with respect to the background stars, but Venus is moving eastward even faster. Watch the distance between Venus and Mars shrink over the next few months.
However, Venus will not overtake Mars during this 2016-17 evening apparition of these two planets. By early spring 2017, Venus will halt its eastward motion and swing back moving westward with respect to the background stars as it approaches its inferior conjunction with the sun in March.
We now have to wait until well after midnight to catch a glimpse of our next bright planet, Jupiter. On Dec. 1, Jupiter rises around 2:30 a.m. in the constellation of Virgo.
Within a half-hour of Jupiter-rise, the bright star Spica rises just to the lower-right of the “king of the planets.” Jupiter is easy to spot since it will be the brightest object in that part of the sky (excluding the moon of course). By the end of the year, Jupiter rises around 1 a.m.
The Geminid meteor shower peaks on the night of Dec. 13-14. Unfortunately the moon is at full phase on this date. As such, only the brightest of the Geminids will be visible.
The Geminids are unique in that they can be seen during evening hours and often show very bright meteors called bolides. So just be patient — sooner or later you should be able to spot a Geminid over the nights of Dec. 11-16.
The winter solstice occurs at 5:44 a.m. on Dec. 21. This marks the sun’s lowest point on the sky in the northern hemisphere and corresponds to the fewest number daylight hours of the year. This also marks the first day of winter in the northern hemisphere. This month’s full moon will occur Dec. 13th at 7:05 p.m. According to folklore, the December full moon is known either as the Full Cold Moon or the Full Long Nights Moon.
The next free public astronomy open house at the ETSU Powell Observatory will occur on Saturday, Feb. 4. from 8-10 p.m. At these open houses, the public can view objects in the sky through telescopes and hear talks by faculty of the Physics and Astronomy Department. Note that the open houses are canceled if the sky is cloudy. Make sure you dress warmly, since you will be standing outside to look through our telescopes.
Further information about these open houses and directions to the observatory can be found on the web at www.etsu.edu/cas/physics/observatory/default.aspx.
This month’s Night Sky was written by Dr. Donald G. Luttermoser, chairman of the Department of Physics and Astronomy at ETSU. He can be reached at [email protected]. Astronomy-related information for the public, including a link to the ETSU Powell Observatory, can be found at www.etsu.edu/cas/physics by selecting the Public Outreach pull-down menu at the top of that webpage.