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    Re: Metal versus plastic or better telescope?
    From: Alan S
    Date: 2012 Mar 27, 15:40 -0700

    Lu Abel:

    On the subject of accuracy, as memory serves, I once saw the following, NOT an exact quote, in a booklet describing the Plath sextant.

    Instrument Error was specified as no more than 12 seconds of arc, across the sextant arc, this was, as I recall, a guarantee. The commentary next went on to note, that on a small yatch, with sea running, the greatest error would come, not from the instrument, but from the operator, who might have great difficulty holding the horizon steady. It was suggested that the user concern himself with that aspect, rather than being overly concerned with "non adjustable instrument error"

    My Astra 111B's "qualification sheet" does not give corrections for various angles, as some I have seen do, rather it states, "This instrument is free of errors for practical use". While this might sound like "lawyers talk" I expect it is the truth. While the prices for Astras, newly purchased, have shown a significant increase in the last few years, they seem to be money well spent, looking at the costs of Plath and Tamaya sextants. By the way, is anyone other than the above mentioned making sextants these days, or have they become, like the slide rule, things of the past.
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