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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Extremely poor conditions??
From: John Huth
Date: 2012 Mar 20, 15:12 +0100
From: John Huth
Date: 2012 Mar 20, 15:12 +0100
Then I don't have a good explanation. Normally you get the kind of curvature you speak of when the surface is hot and the air right at the surface is hot, but the air further above is cool - that's the hot road mirage. I would expect the opposite effect for those conditions, so I don't have a good explanation in that case.
--
Keeping up with the grind
Here's a great website on atmospheric refraction - perhaps you might want to look through it -
On Tue, Mar 20, 2012 at 2:53 PM, Alexandre E Eremenko <eremenko@math.purdue.edu> wrote:
John,But this is "normal refraction", I mean very large, but "in the normal direction": The light ray is curved in the same direction as the
I've heard of a report of some very impressive looming over Lake Michigan
in the spring. I recall that people in a town in Michigan could see the
lights of Milwaukee one night - 80 miles away and well over the geographic
horizon.
Earth surface. This sort of refraction would require NEGATIVE
correction to compensate it. In our case, the refraction had to be
in the opposite direction: the ray had to be curved on the opposite
direction to the Earth surface.
This means that the remote toll bioldings whose tops are normally visible
would be unvisible in these conditions.
Alex.
Keeping up with the grind
