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    Re: Sight reduction method history
    From: Hewitt Schlereth
    Date: 2013 Nov 3, 07:31 -0800
    Lu, older editions of Bowditch have a 15-page chapter "Comparison of Various Methods of Sight Reduction." It's a chronological listing of the various sight reduction methods. I often refer to it when I get curious about what, say, the Kriegsmarine used In WW II. It may have stopped now, but it's still I'm my 1977 edition.


    Sent from my iPad

    On Nov 2, 2013, at 3:08 PM, "Lu Abel" <luabel@ymail.com> wrote:

    Can anyone give, in broad-brush terms, a brief history of celestial sight reduction methods used aboard ships from the advent of reasonably accurate timekeeping forward?

    What method (in very general terms) did Captain Cook use?   Clipper Ship navigators?   The navigator on the Titanic?   Navigators of WW II battleships?

    The spherical triangle that must be solved to compute Hc was well-known from ancient times.   But solving it is error-prone and tedious.   Were logarithms used to simplify the calculations?   When were tabular methods introduced?   How tedious was sight reduction?  Etc.

    As I sit here and bang some numbers into my scientific calculator and out pops Hc and Zn (or, better, my smart phone app simply gives it to me!), I wonder how people did it before the magic of silicon.

    Again, not a treatise, but an overview.



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