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    Re: Sextant precision
    From: Alexandre Eremenko
    Date: 2004 Sep 29, 16:00 -0500

    Dear Members,
    I am answering the questions asked by George
    (and asking new questions that arise from his letter):
    On Wed, 29 Sep 2004, George Huxtable wrote:
    > Alex Eremenko asked about the precision of
    > sextants and sextant measurements.
    > This is a matter which surfaces from time to time on Nav-L,
    I think I read all previous discussions related to sextants,
    all I could find using the search engine.
    > I speak, not as an ocean navigator,
    > but as a small-boat sailor who is never
    I don't even have a small one:-(
    Yet. Just chartering.
    > capable of reading to about 0.1', and
    > calibrated to a corresponding precision.
    That's exactly what I am trying to do.
    > So (for those that don't take lunars)
    I am planning to take lunars.
    According to Fred, star-to-star distances is a good preparation
    for this.
    > is there any point in using an
    > instrument capable of measuring to 0.1', for measuring an altitude,
    No, there is no point.
    > And yet, on this list, the finer points of calibration
    > of these expensive
    > and exotic instruments, ancient and modern,
    > are discussed in detail,
    You are not objecting this, do you?
    > There's another list which is devoted to sextants
    Could you please give me the address?
    > possessions to cherish, or even as investments,
    > rather than as tools to do
    > a job.
    Is not GPS a better "tool for the job"?
    > If Alex is planning to measure lunar distances,
    Yes, I am planning this too.
    In general, I am interested in the history of navigation,
    and history of the instrument making, and history of mathematics
    and astronomy.
    > But if he plans to navigate a small boat by measuring
    > altitudes, then any old sextant will do that job
    When I navigate a small boat I use GPS. But now I would try
    my sextant as well (mostly for fun, and for real experience,
    and to verify various statements on its precision in practical
    > I hope Alex will go ahead with his checks on sextant accuracy,
    > and inform
    > us of his results.
    I will. But I need help from someone more experienced with
    (metal) sextants.

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