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Fred,

On Fri, 22 Feb 2008, Fred Hebard wrote:

> Alex' SnoT also has luminescent paint.
> The luminescence is obtained
> by exposing it to light before use, if I recall correctly.

You recall correctly. However, the light it provides
is not enough for my eyes. I don't know whether this
is a problem with eyes or the luminiscent paint
deteriorated (the sextant is 18 years old).
So at night I have to use a small photo-diod light.

> The use
> of the magnifier with no vernier then
> allows one to read the sextant
> at night without a light.

I find this magnifier very convenient.
It permits reading to 0.1,
much faster than the usual vernier.

> The inverting scope is much lighter
> and slimmer than an equivalent
> binocular, if a bit longer.

It is indeed very much lighter,
has wires in the field of view
(which I find very convenient for many tasks), and I suppose
it lets more light through than a prismatic binocular,
because the light has to pass much less glass: essentially
only two lenses. This is why they have an inverted image
btw. One can easily make the image straight by inserting
one more lens. They did not do it, trying to optimize
the amount of light passing through.

Inverted image creates no inconvenience at all for the
observer, after few hours of practice.

Alex.



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