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Rainbow
Edges demonstrates a phenomenon that has always been
a problem for astronomers and camera makers -- the tendency
of lenses to make rainbows out of white light. In part
one of this two-part exhibit, the visitor can see the
fuzzy rainbows around lights caused by the lens in his
or her own eye. By looking at the purple H, the visitor
sees either sharp red dots surrounded by fuzzy blue
halos, or blue dots with red halos. The eye's lens bends
more blue light than red, so it cant focus both
colors on the retina at the same time. Normally, inhibition
eliminates these rainbows from view, but because red
and blue are at opposite ends of the spectrum, they
are too far apart to inhibit each other. Observable
also is the chromatic aberration of a lens. A colorless
screen of dots, seen through the lens, produces colored
spots. The lens bends different wave-lengths of light
at slightly different angles, which accounts for the
rainbow effect.
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