NavList:

Dear Red and Lu:

> "Aluminum has replaced brass as the material of choice for sextants,"
>  How does it compare for thermal expansion, or rather stability?

A Heath (Hezzanith) booklet I have claims that
"duralumin" (an alloy of aluminium) is superior to brass
as a material for sextant frames. The booklet is of 1930's.
Apparently C. Plath did not share this point of view.

> "electronics." Splitting one prject into two?<G>

Here is my proposal for a "high-tech" modern sextant.
One of the great recent advances is stabilized binoculars.
I think that everyone who has ever tested them should be very
much impressed. The point is that you can have a hand held
binocular now with magnification of 40 and more.
And you can really use such a telescope from a small boat!

A sextant with a stabilized telescope will be able to measure to single
seconds, like a theodolite.
Then I would add a stabilized dipmeter, and the whole combination
of sextant/dipmeter will certainly have performance of
a GPS:-)

Of course you can attach a microchip that will read the angle without
your participation and reduce the observation in a fraction of
a second, so that you will read parameters of your position line
right on the display. Only the most pleasant part remains for you:
actual touching of Sun and the horizon:-)

Stabilized binoculars are sold at about $1200 now,
so I estimate the price of this super-sextant
together with the dipmeter as under $10,000,
even if produces in small lots.



> "4. Automatic height-of-eye calculation. "

Interesting. How do you propose to do this?
On what principle?


Alex.


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