December 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 December 13th. For December, your best viewing nights will be from December 4th to the 16th. The Star chart below is set for Florence, SC on December 15th at 9 pm.

Meteor Shower: 

As you know, meteor showers occur throughout the year but are often not very impressive, averaging only 10-20 meteors per hour. The three most watched showers are the Perseids in August, the Leonids in November, and the Geminids in December. Once or twice in a lifetime, the Leonids may give a spectacular show, but in general, these three meteor showers give moderate displays. In general, the Perseids are most watched because they occur during the warm summer nights.  The Leonids are next in importance because they sometimes have large displays. The Geminids are the least viewed of the three. However, over the many years that I have been watching the night sky, on average, I have found that the Geminids have given the best meteor showers. This year, the Geminids may again shine as the best meteor shower of the year.

Besides the unknown weather factor, the only downside this year is that they will peak late on the night of the 13th and early in the morning of the 14th, during a week night (school and work).  However, the good news is that it will occur during a New Moon.  Another plus is that the Geminids yield many meteors over the few days before and after the peak. So you will probably see many meteors if you stay up late on Friday night after the peak.

As always, meteor showers are only viewed with the naked eye. The reason is that although the meteors appear to come from one area of the sky, in this case the constellation Gemini (see above), they may actually appear in almost any part of the sky. One problem that may occur when viewing meteor showers is a stiff neck. Therefore, a lounge chair is a good viewing aid. I have also sat on the hood of a car, and leaned back against the windshield. This time of year, another problem may be the cold, so bring blankets or a sleeping bag; especially if you use the cold hood of a car. Hot chocolate is another good viewing aid for the Geminids shower.

Most of my readers know that meteor showers occur when the Earth passes though the orbit of a comet. However, the Geminids are not associated with any comet. It is associated with the orbit of an asteroid called Phaethon. As such, it has a much wider debris field which is the reason it yields a good display over many days.

Finder scopes:

Last month I discussed the purchase of a telescope. An important accessory you will need for your telescope is a finder scope. No matter how good you become at visually locating objects in the night sky, you still have to be able to aim your telescope at your target. Every telescope comes equipped with some type of “finder scope.” Traditionally, these finder scopes attach to the side of your scope, and are just small low power telescopes, usually 6 to 8 power, and they usually have crosshairs in the lens to aid in locking the telescope on your target. Now the “problems”: These small finding scopes usually give an upside down and reversed image, which may or may not match the image of your telescope. In addition, and probably the most frustrating is that in general, finding scopes give a small an angle of view.

So what is the best way to aim your telescope? There are two very effective aiming devices. The simplest and cheapest is a Red Dot Finder. The better and more expensive device is a scope mounted Green Laser.

First the red dot finder. The red dot finder does not use a red laser. It uses a red LED light. The LED is somewhat hidden in the back, and a reflection of the light is seen on a plain glass section in the front. As you look through the finder, you will see the red dot on the glass surface. You then simply overlay this red dot on the dark sky, and place it on your target of choice. The red dot finder A below is about $40, and finder B about $70. Finder B has a larger field of view, and also has four different red shapes to overlay on the sky, which is a nice touch. (C below)

Second, is the Green Laser Finder. Attaching a green laser to your telescope is a great way to aim your scope. You can see exactly where your scope is pointing as you stand next to your scope and move it around; at ScienceSouth, we use a green laser on our Dobsonian telescope. The complete laser and telescope mount is shown on the left below and sells for $120. The image on the right shows how easy it is to aim a green laser mounted telescope.

Naked Eye Sights:  The Geminids meteor shower peaks in the early morning hours of December 14th. The sky will be dark, and it is expected to be a good shower. Don’t forget to look for meteors the night before and the night after the peak.

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, in color.

See you next month!

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