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>40a2a958$1@news.povray.org...
>> Remember that we are inside the atmosphere which causes the apparent
>> size of the sun to change from what it would be viewed from the same
>> distance in space. In particular, the sun appears bigger when it's
>> near the horizon, which is the case here...
On Thu, 13 May 2004 09:25:07 +0200, "Marc Jacquier"
<jac### [at] wanadoo fr> wrote:
>That's half true: light rays bend due to gradient air density and variable
>ior but that flattens sun image rather than inflates.
This is why the Sun appears oval at sunset.
>Bigger sun near the horizon is mostly an illusion due to possible comparison
>with known references.
>Our brain believes that sun is on the same skysphere as the sky which is
>far at the horizon.
>As angular size of the sun remains the same, our brain "thinks" it is bigger
Marc is correct; it's a psychological illusion, not an optical
effect. Photographs prove this. More information is available at:
http://science.nasa.gov/headlines/y2002/24jun_moonillusion.htm
>Try (not too long eh?) looking at the sun through a tube when it is low, so
>you make abstraction of surrounding and you get rid of this illusion.
Better with the Moon! The illusion is the same, but you get to keep
your eyesight.
I've also read that looking at the Moon upside-down will also kill the
effect. This exercise came with the suggestion that you not try it
where other people can see you. ;-)
--
------------------- Richard Callwood III --------------------
~ U.S. Virgin Islands ~ USDA zone 11 ~ 18.3N, 64.9W ~
~ eastern Massachusetts ~ USDA zone 6 (1992-95) ~
--------------- http://cac.uvi.edu/staff/rc3/ ---------------
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