Friday, January 6, 2012

January 2012

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 23rd. For January, your best viewing nights will be from January 14th to the 27th. The Star chart below is set for Florence, SC on January 15th at 9 pm.

Star Names:

Learn the names:

If your hobby is bird watching, one would expect you to know the names of several birds. Therefore, I find it amazing that many amateur astronomers know several constellation names but only a few star names. Let’s take some time this month to discuss the topic of star names.

Since most amateur astronomers know the names of many constellations, this is where you should begin to learn the names of several stars. Most constellations do not have one prominent bright star, example: Big and Little Dipper, Orion, Cassiopeia, Gemini, Sagittarius, Hercules, Pegasus, and Perseus. However, many constellations do have one bright prominent star. If you know these constellations, then you should be able to name that bright star. Here is a list of common constellations and the name of the brightest star in that constellation: Leo the Lion; brightest star is Regulus, in Bootes; Arcturus, Auriga; Capella, Cynus; Deneb, Taurus; Aldebaran, Canis Major; Sirius, Scorpius; Antares, Lyra; Vega. You now have eight star names to begin your list.

In addition to memorizing the name of the brightest star in the well-known constellations above, here is another star name challenge you should try. Choosing the well-known constellations, the Big Dipper (really an asterism) and Orion; memorize all the prominent stars in these two constellations.

Let’s start with the Big Dipper. There are seven stars in the Big Dipper. Starting at the end of the handle you have Alkaid, Mizar, Alioth, Megrez, Phecda, Merak, and Dubhe. See image below.

Additional information: A line starting with Merak and going through Dubhe will point to the North Star (Polaris). Another feature of the Big Dipper stars is the star in the middle of the handle, Mizar. Mizar is a double star, and its companion is called Alcor. On a clear night you can see the faint Alcor above Mizar. If you have trouble seeing it with your eyes alone, it is easily seen with simple binoculars. Add Alcor to your list of star names; now you know eight stars in the Big Dipper.

The constellation Orion also has eight stars that you should learn. Remember, Orion the Hunter forms the shape of a man. The eight stars are as follows: Meissa is the head. His right shoulder is Betelgeuse, the left shoulder is Bellatrix, the right knee is Saiph and the left knee is Rigel. The three belt stars starting on Orion’s right side are Alnitak, Anilam and Mintaka. See image below.

Additional information: Meissa is much dimmer than the seven other stars. Betelgeuse is a red giant star, and its orange color is obvious. Rigel is a hot blue star. Note that I did not list the names of the three apparent stars in Orion’s sword. That is because the top “star” in the sword is really multiple stars imbedded in the Running Man Nebula. The center “star” is actually the Orion Nebula (M42) and the bottom “star” is also made up of multiple stars.

If you learn the names of all the stars I suggested above, you will have 24 star names in your memory bank; a good amount for a new amateur astronomer.

What do the names mean?

Every star name has a meaning, but let’s just focus on some of the stars we learned above. First note that many stars start with the letters Al. This is because many of our star names were given by ancient Arabs, and in Arabic, Al means “the.” Therefore, the star Al-debaran means “the follower” (of the Pleiades). In Orion, the three Arabic names in the belt are, Al-nitak; “the belt,” Al-nilam; “the string of pearls,” and Mintaka which is another Arabic word for belt. Of course, some Arabic star names can be quite difficult, such as Zubeneschamali; “northern claw;” ( Zoo-Ben`-Ess-Sha-Mah`-Lee).

How do you pronounce the star names?

In general, most star names are pronounced as expected from their spelling; however, there are many are not pronounced as expected. One example is the bright star Vega in the constellation Lyra. Most of us say “Vay`-ga,” however, the official pronunciation is “Vee`-ga.”

I have found over the years that astronomers sometimes disagree about the “correct” pronunciation of certain stars. I do not worry that much about the pronunciations; I still prefer to say “Vay-ga.”

Many years ago, a friend asked me an interesting question; “Do any stars have a person’s common name, such as Joe, Mary, Sam, etc.” The answer is that only one star has a name that is pronounced but not spelled as a person’s name. In the autumn, when the Northern Cross (Cygnus) appears upright, the star marking the left side of the cross is called Gienah, and is pronounced like the women’s name, Gina. See below.

Naked Eye Sights: Orion is always a joy to look at high in the January sky. If you have any friends that have no knowledge of astronomy, introduce them to the constellation Orion. Jupiter is still visible in the southwest, and Venus will continue to shine brightly in the west after sunset. Venus will continue climbing higher in the sky until early May.

Binocular Sights (7 to 10 power): Check out the Orion Nebula, and the Moons of Jupiter.

Telescope Sights (60-100mm: If you received a telescope for Christmas, Jupiter is still a great target in the southwest throughout January.


See you next month!