NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: sextants on aeroplanes
From: Jeremy C
Date: 2008 Dec 13, 04:58 EST
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From: Jeremy C
Date: 2008 Dec 13, 04:58 EST
Snip
Sextants and quadrants allow a greater
range of measurement which might be useful for lunar distance
measurements, horizontal sextant angles for coast wise navigation and in
the rare case of a body within 30º of the zenith with an obstructed
horizon below it but a clear horizon in the opposite direction in which
case the navigator could turn his back to the star and use the opposing
horizon for the sight. (I don't know if this was ever actually done in
real life.)
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This has been done in practice at sea. I have done it several times
in the tropics when the sun is high. Typically because at the regular
azimuth there is a thunderstorm that obscures or muddles the true horizon
but there is a perfectly good horizon 180 degrees out. Shoot a backsight,
and you are good to go; as long as you remember how to do it. It is also
in the US Coast Guard tests, but mostly as Hs to Ho reductions.
Jeremy
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