Wednesday, April 29, 2009

A-Hunting We Will Go

Visitations by major comets, such as Comet Hyakutake in 1966 and Hale-Bopp in 1997, are newsworthy events. Turn on the television or read a newspaper, and you’ll be told where to look and when. But most comets don’t make the front pages. For the latest comet news, check out the NASA comet home page at Sky and Telescope magazine also publishes comet information Of course, you don’t have to limit yourself to looking for comets whose presence or approach is already known. You can head out with your trusty telescope and hunt for new ones.
Comet hunting can be done with or without a telescope, but a good telescope greatly increases your chances of finding a new comet. Remember that telescopes catch more light than our eyes, and most comets are discovered as a tiny, wispy smudge. The coma will not appear much different from a star, but you should see a gradual, not sharply defined, tail attached to it. The tail may be a short, broad wedge or a long ion streamer.
The following tips will increase your chances of finding a comet:
  • Set up your telescope in a rural area, away from city lights. Choose a moonless night so that the skies are as dark as possible. You will be looking for a faint object.
  • According to David H. Levy, just before dawn, two days before or five days after the new moon, is an ideal time to search.
  • Comets can be seen in any part of the sky, but they are brightest when they approach within 90 degrees of the sun. You might concentrate on this part of the sky. That is, at sunset you could look from directly overhead to the western horizon.
  • Gradually and methodically sweep the sky with your telescope. Stake out perhaps 40 degrees of sky and sweep in one direction (either from east to west or west to east).
  • Remember one thing. Discovering a comet requires you to see something unusual or different in the sky. For this reason, you would do well to spend time becoming familiar with the sky, the constellations, and your telescope, so that you will be better able to recognize when something is not quite right.

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