Moon Illusion


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The illusion that the full moon appears larger when seen near the horizon—because perspective is provided by buildings, trees and other landscape—and smaller when seen near its zenith
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Desaguliers' experiments on apparent size were stimulated by his speculations on the link between size and distance perception in the moon illusion. He pointed out, as had many others previously, that the horizon moon is perceived as more distant than at its zenith.
"Our results leave no doubt that perceived-distance information plays a primary role in creating the moon illusion," Lloyd Kaufman says.
However, (http://science.nasa.gov/science-news/science-at-nasa/2008/16jun_moonillusion/) as NASA notes, airline pilots have witnessed the Moon Illusion at high altitudes, where there are very few buildings about.
In The Mystery of the Moon Illusion (Oxford University Press, 2002), two academic psychologists, Helen Ross and Cornelis Plug, remind us that the size illusion distorts other things in the sky.
The corona appeared golden yellow with a greenish tinge, and, thanks to the Moon illusion that works for objects near the horizon, it loomed unusually large against the twilight sky.
From Haidinger's brush to the Moon illusion, Out of the Blue introduces us to some of the most celebrated and bizarre atmospheric and optical effects visible to the naked eye.
"The result," O'Meara continues, "was what I liken to the deep-sky version of the famed Moon illusion. Once I considered the vast distances between the Earth and the two objects, as well as their relative sizes, the Crab suddenly swelled in my mind's eye.
We got a sense that the Sun loomed extraordinarily large over the water - a solar counterpart to the famous "Moon illusion."
Countries near the center of the Earth's Moon-facing hemisphere will experience the eclipse practically overhead, while those along the rim will have the Moon very low in the sky, "magnified" by the well-known Moon illusion and perhaps nicely framed by distant landmarks.
"Because of the Sun's exceedingly low altitude, the famous 'Moon illusion,' made the Moon and Sun appear enormously large over the water," said Rao.
Here's a small sample: iridescence in dewdrops, mirages, the red flash, black snow, the Moon illusion, imperfect images formed by the eye, freak reflections, illusions concerning rest and motion, pillars of light on roadways, a cat's eyes at night, reflection of light on mosses, scintillation from stones, and will-o'-the-wisps.
Consider the familiar Moon illusion: the Moon seems larger when it is near the horizon than when overhead, though it hasn't changed size at all.