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    Re: averaging devices on sextants
    From: Alexandre Eremenko
    Date: 2004 Oct 8, 09:06 -0500

    Thank you to all for interesting information in reply
    to "Averaging". There is one point on which I think additional
    comment is necessary:
    On Thu, 7 Oct 2004, Ken Gebhart wrote:
    > The idea of averaging sextant readings using a marine sextant,
    > (ie. instead
    > of using a bubble), really has no basis because acceleration
    > has no effect
    > on it.
    The procedure of averaging observations using a marine sextant
    is recommended by many books and manuals, from XVIII century
    to these days.
    It is not specific to bubble horizons or effects of acceleration.
    It is also used on land.
    The purpose of this procedure is to increase precision.
    In fact this is a standard procedure increasing accuracy of
    ANY scientific measurements.
    The theoretical foundation of this procedure lies in
    the "Method of Least Squares" by Gauss. The most
    comprehensive discussion
    in the context of practical astronomy
    of this theoretical basis is contained in the last chapter of
    Chauvenet's 2-nd volume.
    The specific of aerial observations is that the random error
    coming from acceleration is very large, and the averaging has
    to be done quickly. That's why they have a built-in mechanism,
    integrator, that does it automatically.

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