Sunday, June 27, 2010

Detecting comets and asteroids before they are obvious.....

When out at night moonlight casts a wonderful spell. In addition to reflecting the light of the nearby star, it polarizes the light. Viewed through polarizing plastic, whether or not contained in high quality glass, the light will dim and slowly disappear as the linear filter is rotated until nearly all the light is gone!

Whatever the source of the light from a star it is clearly not polarized. When an object reflects the light, it is polarized and thus we receive a tiny amount upon earth. By employing suitable means and a polarizing filter it should be possible to leave an image on a "computer screen" that shows many faint objects that are not self illuminating, but reflect polarized light only.

Taking a "shot" of the night sky will virtually fill the image with light. Taking another, longer one, to account for the roughly one quarter reduction in light caused by the filter, will show all the self illuminating objects less those that reflect. It may need two or three such shots, taken with a one third rotation of the polarizing filter, to eliminate all the reflecting objects. Taking a negative of the first shot and combining it with each of the others will eliminate all the self illuminating objects. What is left is asteroidal with the occasional plotted and named object among them. Repetition of this over time will enable plotting and ascertain the degree of likely proximity to be expected over the near future.

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