NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Celestial Navigation at NEAF
From: Stephen N.G. Davies
Date: 2015 Apr 20, 21:58 +0800
Sent from my iPhone
From: Stephen N.G. Davies
Date: 2015 Apr 20, 21:58 +0800
What was 'obvious' was the need for someone with the relevant knowledge of what might seem to the uninitiated (like me) a puzzle about the difference between a mirror and a pan of engine oil to clarify why Lt Cmdr John Bingham was right, supposing he was. That has now been provided. Thank you.
Stephen D
Sent from my iPhone
Despite initial impressions, the proportion of incident light that is specularly reflected by a particular fluid/air interface is far from "obvious" and is only loosely associated with the overall absorption of light ("darkness") of the fluid. (See: http://en.wikipedia.org/wiki/Specular_reflection.) For example, highly-polished deep black marble can exhibit a very strong specular reflection. The specular reflection of the celestial body is what we're looking at in an artificial horizon. Used engine oil and molasses *could* do a very fine job of it!
--Paul
