Star date: 11:15:98
The Season of Meteors
Nature is delighting the Earth with a special treat. Shooting stars for the holidays.
There are nine major meteor showers which are visible from Earth each year. Novemer has two, the Taurids in the first week of the month, and the Leonids, which are visible this week. Each December, the Geminids delight people worldwide with around one meteor per minute from the 10th through the 13th of that month.
Meteor showers are caused when the Earth passes through the debris left by a decaying comet. When they comet has just passed the orbit of Earth, it leaves much more material behind. When the Earth then goes through that cloud of rock and ice, a meteor shower results. If any shower is very heavy, it can be refered to as a meteor storm.
The comet associated with the fabulous Leonid meteor shower this year is named 1866 I Temp. A rather ordinary sounding name for a comet which produces such beauty as a major meteor shower.
The Geminids next month are always sure to delight, producing about 50 meteors per hour, centered around the constellation Gemini. They are also predicted to put on a spectacular show this year.
The best time to view almost any meteor shower is just before dawn, facing to the south. In the evening, these periodic meteor showers can be seen to the east, but the meteors often go below the horizon, so you do not seem to see as many as just before dawn.
It is fairly easy to determine exactly where to look for meteor showers, as they appear to come from an area around the constellation which they are named after. Simply look up where that constellation is at any time on a star map or using astronomy software.
Meteor showers are probably the easiest form of astronomy for the amateur. No special equiptment is needed, except a pair of eyes, perhaps a chair, and a few minutes or hours to spare. They are highly predictable (each occuring at around the same time each year), and last over the course of a few days. When a shower is predicted, simply go outside at night (which can be the greatest challenge this time of year), set up a chair facing east in the evening, or south in morning, look up, and enjoy.
When you go out to view meteor showers, there are a few things you can do to improve your viewing experience. First, especially at this time of year, is to dress warmly. You'll be amazed at how cold you can get at night doing astronomy in the late fall or winter. Second, bring a thermos of hot coffee, tea, or cocoa with you, to keep your insides warm. A sandwich or some other form of carbohydrate would be helpful, providing energy for an observing session of any length. If you are observing a meteor shower for a few hours, make sure to take occasional breaks, perhaps observing for 50 minutes each hour, punctuated by 10 minute breaks.
A fun idea is to take a photograph of the meteor shower. Since each meteor is visible for at most a few seconds, it would be nearly impossible to take a photograph of an individual meteor. It is possible though, to take a photograph of a shower by exposing a frame of film for a long time. Point the camera towards the area from which the shower will be eminating. Make sure it is on a steady surface.
Then set the camera to the "B" setting, and expose the frame for between a few minutes and a few hours. The result you will get will be a picture of arcing star trails with meteor streaks shooting through and across them. The star trails are caused by the rotation of the Earth. For best results, use what is called a cable release. This is a cable, available at any camera shop, which screws into the trigger of a 35mm camera, and lets you expose the shot without jiggling the camera. Then, you can set the lock on the cable release to keep the frame exposed for however long you choose.
Clear skies, and good viewing.
