Two On A Big Ocean The Story of the First Circumnavigation
of the Pacific Basin
in a Small Sailing Ship


      

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Re: Question about Davis Mk 25 sextant beam converger

From: Fred Hebard (no email)
Date: Mon May 08 2006 - 13:26:29 EDT

  • Next message: George Huxtable: "Re: Question about Davis Mk 25 sextant beam converger"

    Right,

    One needs to check IE each time the sextant is used. But one doesn't
    need to ADJUST IE to zero each time.

    Fred

    On May 8, 2006, at 10:45 AM, Red wrote:

    > Greg-
    > Even with a better sextant, it is "proper" practice to check for
    > IE every time you use the sextant. I've seen IE hold at zero for a
    > zero, even with changing temperatures, but all it takes is one
    > bump, one slip, and then your sights are down the drain. Far more
    > "professional" to check it every time so you know it hasn't
    > changed, instead of assuming so.
    > The plastic sextants are supposed to be less stable with
    > temperature change, so that taking one from a warm indoor home out
    > into cold air, or taking one and leaving it in hot sunlight, etc.,
    > all can cause thermal changes in the frame, which bring changes in
    > the IE.
    >


  • Next message: George Huxtable: "Re: Question about Davis Mk 25 sextant beam converger"



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