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I should clarify an important point: I've never been to the pole, however, I
have travelled over terrain and sea ice which offers similar challenges:
featureless, cold and miserable.

Theodolite vs. sextant: it is a matter of weight. Theodolites are simply
heavier. And it is matter of simplicity. Sextants are easier to use than
theodolites. Simplicity is of the utmost importance when operating in
extreme cold conditions. Even the simplest of tasks becomes difficult and
time-consuming under conditions of extreme cold. Unless you have experienced
this first hand, it is a difficult concept to convey.

As for adjusting the mirrors, one can use the sun or moon semi-diameter or,
failing that, distant objects, such as ice blocks or icebergs, can be used
quite effectively.

With regard to Scott, I cannot remember where I read that he took a
theodolite. It could have been in Roland Huntford's book, "Amundsen and
Scott".

cheers,

Robert Eno


----- Original Message -----
From: Peter Fogg 
To: 
Sent: Wednesday, September 11, 2002 10:55 PM
Subject: Re: On polar nav


> Good on you, Robert, you're a mine of information. But if the theodolite
tripod
> can be detached from the rest then the instrument part is similar to a
sextant
> (?) but would seem much more useful - no worries about a horizon or
auxillary
> equipment to replace same, and the instrument could be left standing for
the 24
> hour period under discussion; just swung around, kept level with its
> bubble-levels? The tripod is not much more cumbersome than a rifle, for
> example, which no self-respecting explorer would be seen without.
>
> Which led to another thought - how do you check for index error without a
> horizon?
>
> What a terrible thing, to talk about being dead wrong about Scott.
>
> Robert Eno wrote:
>
> > I can answer the last question:
> >
> > Theodolites are heavy instruments to lug around on a trip to the pole.
But
> > most importantly, ever try to use one at -30 C?  It ain't fun, believe
me. A
> > sextant is much easier and simpler, to work with under extreme
conditions
> > and compared to a theodolite, a little more robust.
> >
> > I think, but am not entirely certain, that Scott took a theodolite with
him.
> > I could be dead wrong though.
> >
> > cheers,
> >
> > Robert Eno
> >
>
>

   

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