Re: [Phys-l] moon illusion measurement

[WC Maddox <maddox@physics.Auburn.EDU>]

From: WC Maddox

Look at the photographs on this web site to see how much effect 
refraction can have on the size and shape of the Moon:
http://newburyas.wordpress.com/2009/10/26/the-moon-illusion/



Stefan Jeglinski wrote:
> Based on geometry, and ignoring refractive effects that influence the 
> perceived size, the angular extent of the moon at zenith is somewhere 
> in the neighborhood of 1.5-2% larger than at horizon, and expected 
> that to be reflected in the pictures, thus lending credence to the 
> accepted notion that the large "horizon moon" is an illusion. I was 
> surprised instead to find a significant discrepancy in the pictures. 
> They confirmed that the moon was larger in extent at zenith, but the 
> magnitude of the difference was quite significant.
>
> Z