M G J Minnaert goes into it in some detail (several pages) in "Light and Colour in the Outdoors", but in summary, it's because the sun is lower in the sky and the additional air pressure crushes it a bit.
No, no - actually he says it's an ordinary mirage. "A fairly good approximation is obtained if you assume that there is a sudden bend in the light ray coming from the sun when it strikes a layer of discontinuity. Remember that such a layer follows the curvature of the earth. However, the light ray must be assumed straight before it reaches the layer and after it has passed through it." He then provides a couple of illustrated case studies and some simple mathematical proofs which are way beyond me. Hope this helps. I'll bet you saw a lot of it in on your walkabout. Or is it called a 4WDabout now? Anyway, welcome back. -- Cheers, Bob > -----Original Message----- > From: Rob Studdert [mailto:[EMAIL PROTECTED] > Sent: 26 September 2005 08:46 > To: [email protected] > Subject: Distortion low on the horizon > > Does anyone know the technical reason that the sun renders as > an ellipse when shot close to the horizon? > > TIA.
