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Subject: Re: accuracy of automatic celestial navigation
From: Robert Eno (enoid@XXX.XXX)
Date: Fri Dec 06 2002 - 23:24:32 EST
We have to differentiate between observations at sea and observations on
land with an artificial horizon.
I agree that 2 miles at sea is acceptable and indeed satisfying, although I
have known some mariners who claim that they have no problem with obtaining,
consistently, accurate fixes to within less than a mile.
I know that on land, I am very displeased with myself if I cannot pin myself
down to within less than a mile -- even with a bubble attachment -- and I am
not even all that proficient. At sea, 2 miles is fine for me, although I do
like to do better if I can. There was an interesting article in Ocean
Navigator several years ago in which the Captain of the ON training vessel,
Ocean Star, obtained a perfect pinwheel fix at sea. Can't remember her full
name: Virginia _______ but she is apparently a superb seaman and a skilled
navigator. Some folks just have the touch.
In the final analysis, and in looking at the discussions on how to get more
accurate observations, it seems a tad overkill -- at least for PRACTICAL
navigation purposes -- to carry along things like "Gavrishell dipmeters" and
such. Please note that I am not ridiculing the idea but in reality, the
ordinary seaman or yachtsman is probably not too concerned if s/he doesn't
hit the bullseye. In mid-ocean, it just doesn't matter (except inasmuch as
bragging rights over a tot of rum). Close to shore, it does, however, that's
when one can start to employ coastal navigation techniques.
And I can't imagine trying to wield a full sized bronze sextant with a 20
power scope. Good Lord, my 6 x scope is heavy enough!
I do, however, really like the idea that an automated astro-navigation
system can achieve the kind of accuracy described by Jared Sherman. In this
age of GPS supremacy, it constitutes astro-navigation's "revenge of the
nerds". Makes me feel warm and fuzzy all over!
Robert
----- Original Message -----
From: George Huxtable <george@XXX.XXX>
To: <NAVIGATION-L@XXX.XXX>
Sent: Friday, December 06, 2002 7:05 PM
Subject: Re: accuracy of automatic celestial navigation
> For those of us that sail our small craft out at sea, my opinion is that
if
> we can achieve a precision of 2 min, we are doing pretty well. What do
> others think?
>
> George Huxtable.
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