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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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