January 2013

Tony Martinez

                                  Tony Martinez

Each month I will describe sights of interest in the night skies of South Carolina.  These sights will be broken down into three sections; what you can see with the naked eye, with binoculars, and with a small telescope. The best time to view the night sky is at and around the times when the Moon is not visible, what is known as a New Moon; which will occur this month on January 11th.  For January, your best viewing nights will be from January 3rd to the 15th. The Star chart below is set for Florence, SC on January 15th at 9 pm.


The “Year of the Comets?”

 A comet is like an icy snowball a few miles across containing ice, gases, and rocks. Periodically they enter into the inner solar system, and as they swing around our Sun, they can become very bright, and exhibit a long “tail” of particles blown off the surface of the comet by the Sun.

There is a high probability that you will see at least one impressive comet in your lifetime.  Actually, you may see three or four, or more! In the last century there were only two impressive comets, Arend-Roland in 1957, and Hale Bopp in the spring of 1997. There were also some modest comets like Hyakutake and West, and of course there were some highly publicized washouts like Comets Kohoutek and the return of Comet Halley in 1986.

The year 2013 may bring us the next comet to remember, but as always with comet brightness predictions, it could also end up as another dud.  This new comet was just discovered and is named Comet ISON.  ISON is a long way out, between Jupiter and Saturn, and is not expected to be close to the Earth until next Thanksgiving.  The image below shows its discovery.


Astronomers do not like to make early predictions of the brightness of comets, for fear of public ridicule when the comet is unimpressive.  Therefore, don’t expect to hear much about ISON in the news for several months. You may be wondering if it is so hard to predict the brightness of a comet months in advance, why are the astronomers even mentioning ISON at this time.  Although it is difficult to predict a comet’s display, it is easy to determine its exact path on its journey into the inner solar system.  Remember, the bright tail of a comet is caused by particles blown off the comet’s surface by the energy of our Sun. Therefore, what may determine how bright a comet will be, is how close it passes by the Sun. Calculations of ISON’s path place it extremely close to our Sun at the end of November. The most recent impressive Comet was Hale-Bopp in 1997.  Hale-Bopp’s closest approach to the sun was 84 million miles. Comet ISON is expected to pass about 1.2 million miles from the Sun; 70 times closer!

I will continue this discussion later this year when we have a better indication of what to expect from Comet ISON.

Observant readers may have noticed that I titled above, the year of the comets; plural.  While waiting to see if Comet ISON will be the greatest comet of our lifetimes, there is a second comet inbound this year.  Its name is Comet PanSTARRS, and it should be visible in early to mid-March.  As of now, Comet PanSTARRS is “under the Earth,”  and is only visible telescopically to observers in the southern hemisphere.  Once it goes around the Sun, we should see it, beginning about March 7th.  As always, this comet may also prove to be a washout.  The image below is the Starry Night program’s prediction of PanSTARRS as seen from ScienceSouth on March 8th.


Geminids Report:

I hope that you had a chance to see the Geminids last month.  The ScienceSouth astronomers went west of Florence to find some decent dark skies. We viewed from 12 midnight to 2 am.  The Geminids meteor shower yielded between 60 and 70 meteors per hour at our location; this is considered a very good meteor shower.  We saw several very bright meteors, some that broke apart, and my personal favorite was two meteors that traveled side by side, one very bright, and one medium bright; as represented below.

Double Meteor

Another interesting aspect of this meteor shower was the locations of the various meteors.  As I have often mentioned, meteor showers appear to radiate from one area of the sky, which accounts for their names.  In this shower, they should radiate from the direction of the constellation Gemini in the east.  However, on the night of the 13th/14th, the meteors appeared everywhere in the sky, including on every horizon.  Another oddity of this Geminid shower was the large amount of meteors seen in the western sky, opposite the position of Gemini. The answer might be due to Comet Wirtanen.  This comet was discovered in 1948 and between the 10th and the 15th of December was the first time that the Earth has passed through its orbit. If Comet Wirtanen did produce its own meteor shower, it would be in the region of Pisces, and by midnight, Pisces was low on the western horizon.


The two best planetary targets for amateur telescopes are Saturn and Jupiter.  You can start the New Year by turning your telescopes to Jupiter.  There is no need to rush because you will be able to view Jupiter from now into the middle of April.  Saturn will then return into view from mid-April until the end of July. Therefore, this year we will have a total of seven continuous months of good planet viewing.

Naked Eye Sights:  Orion, Taurus, Sirius and the Pleiades Cluster.

Binocular Sights (7 to 10 power):  Jupiter is a good target this month. Check out Jupiter’s moons.  Move to the right of Jupiter to see the open cluster, Hyades.

Telescope Sights (60-100mm):  Try to see the Jupiter’s atmospheric bands of clouds, hopefully in color.

See you next month!

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