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    Re: Classic Trig Log Sight Reduction Revisited
    From: Hanno Ix
    Date: 2014 May 28, 08:27 -0700
    Gentlemen

    Re: Sight reduction by hand

    I am happy Greg initialized the most recent discussion about
    sight reduction by hand. It is a very noble art demanding
    precision and concentration - like everything else in CelNav.
    To make things easier I drew up the azimuth diagram you
    seem to like.

    May I, in this vein, direct your attention to another
    simplification that occurred to me some time ago:
    A method that circumvents virtually all concerns of others.
    Some months ago I described it in my memo to navlist named
    Sight Reduction by Hand you may like.

    You may want to look it up. 
    It involves generally just 4 digit integers, mostly only addition and subtraction
    and multiplication/division solely by 2 and 4. It handles positive
    and negative angles with equal ease and is accurate at high latitudes.
    And it employs a trig table - not log trig table - of just 2 pages.
    I am surprised it has not found takers so far.

    Included in the memo are the table, a worksheet, a narrative and an example.
    Give it a try.

    Hanno


    PS: there is an errata in the narrative - easy to spot :(






    On Tue, May 27, 2014 at 9:21 PM, Greg Rudzinski <NoReply_Rudzinski@fer3.com> wrote:

    Thanks Frank. The pictured index card shows an example of a classic trig log sight reduction for a Sun observation made earlier today with a bubble octant.


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