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From: George Huxtable (no email)
Date: Sat Jun 04 2005 - 11:31:23 EDT
There are some strange comments in Peter Fogg's posting.
Referring to latitudes in which the Sun approaches the zenith, he comments
that the practical difficulties "mean that noon sights in such places may
be notable by their absence".
And yet, the whole recorded history of navigation tells us that whenever
the sky was clear at noon, taking an altitude of the Sun was an inflexible
rule for any vessel, whether in the tropics or not, in spite of those
practical difficulties that Peter refers to. Perhaps those navigators were
made of sterner stuff than he is. Does he have any evidence to show that
noon sights were ever skimped or avoided in the tropics? I doubt it.
"Notable by their absence"? Nonsense.
And he adds the curious comment "plus the awkward contortions of trying to
take a sight of the blazing Sun with the head tilted back at 90 degrees to
the body." It makes me wonder if Peter himself has ever taken a sextant
sight of the high Sun he refers to (I haven't). The process involves
bringing the Sun down to the horizon, not vice versa, so there's no need to
look up, at all. What IS he talking about?
Bill suggested that there was some value in discussing "longitude by noon
Sun", if only to point out why it a bad idea.
To which Peter replied, even more curiously-
"Nah, it's all grist to the mill. There's nothing good or bad, as
Shakespeare said, only thinking makes it so... If it serves a useful
function (at least when it comes to nav) then its all good. Not perfect,
mind. Good is simply good."
Well Shakespeare is hardly a relevant authority to call in aid on such a
question. The problem about a navigator learning such a bad and inaccurate
way of determining longitude is that it displaces from his mind the right
way to do the job.
George.
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contact George Huxtable by email at , by phone at
01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
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