
NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Plumb-line horizon vs. geocentric horizon
From: Frank Reed CT
Date: 2005 Feb 10, 03:33 EST
From: Frank Reed CT
Date: 2005 Feb 10, 03:33 EST
Pierre Brial wrote:
"In the place where I live the deflection
is 0.7', which is considered one of the highest in the world. As I
understand that a bubble sextant is not that accurate, this should not
affect navigation. Nevertheless, If you need accuracy, you have to take
it into account when you use a theodolite."
is 0.7', which is considered one of the highest in the world. As I
understand that a bubble sextant is not that accurate, this should not
affect navigation. Nevertheless, If you need accuracy, you have to take
it into account when you use a theodolite."
Interesting!
In the water off-shore of Reunion, there should also be a deflection
(diminishing rapidly with distance) and 0.7' would be observable,
though with difficulty, using a standard sextant. Have you had any opportunity
to use your sextant at sea?
Speaking of Reunion, the famous navigator, Nathaniel Bowditch, visited
Reunion on one of his earliest ocean voyages. According to Berry, his
biographer, Bowditch spent five months there. His logbook and other notes
from this trip are still in existence. Bowditch found the French women of the
island scandalous and wrote "they are too bold... nothing puts them to the
blush". They embarassed him by exposing their legs (happy mardi gras,
everybody). That was in 1795. Nathaniel Bowditch by all accounts was a frail,
almost elfish man, quite a bit shorter than average and prematurely grey at the
age of 23, and I think they may have enjoyed making sport of him.
-FER
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars