Thread: What is this?
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Old 12-05-2011, 10:17 AM   #1839
glatt
 
Join Date: Jul 2003
Location: Arlington, VA
Posts: 27,717
OK, so I guess you count the number of fat trees in the woods. And you use the metal gauge to see how fat the trees are so you know whether to count them or not based on how much each tree fills the window. I'm guessing the prisms work by either completely splitting the image of the trunk if the tree is too small to be counted, or else leaving a little bit attached if the tree is fat enough to be counted.
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