Archived posting to the Leica Users Group, 1999/12/21
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]If it was refraction (*not* diffraction), the moon would subtend a measurably greater angle. This change in size would not be an illusion, as it would be measurable. This is not the case. One common reason that is given for the optical illusion we've all experienced is that when the moon is close to the horizon it is near familiar objects that give us a sense of scale. When it's overhead, divorced from all reference points, our brains judge its size in relation to all the empty space around it, and it therefore appears smaller. Check out http://facstaff.uww.edu/mccreadd/ for a very complete article on this illusion, along with a theory called about its cause, which according the Professor Emeritus who wrote the article, is something called "oculomotor micropsia". Paul Chefurka - -----Original Message----- From: Eric Welch [mailto:ewelch@neteze.com] Sent: Tuesday, December 21, 1999 10:39 AM To: leica-users@mejac.palo-alto.ca.us Subject: Re: LUG[Leica] Re: Re: Moon beams sometime around 12/21/99 3:24 AM, George Huczek at ghuczek@sk.sympatico.ca was heard to write: > This is a popular misconception that I thought was cleared up earlier. To > repeat, it is an optical illusion, and only that. And what do you think an optical illusion is? Diffraction could very well be the case of the illusion. Nobody thinks the moon really gets bigger. - -- Eric Welch Carlsbad, CA http://www.neteze.com/ewelch "You can't cajole someone into loving you by simply being nice to be around." - Garrison Keillor - As heard on "A Prairie Home Companion"