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    Re: Poor Line of Position Computer/popularity of slide rule sight reduction
    From: Brad Morris
    Date: 2010 Jan 14, 10:27 -0500

    Hi Chuck


    I think that Ronald van Riet’s 2008 paper { find it here } will answer many of your questions.


    Economics certainly played a part.  In the 1940’s war years a 10 degree volume of HO214 was only $2.25, as printed in each of my volumes.  It is generally assumed that a Bygrave (or its close relative the HR-1) cost more.  It would be interesting to see just what 180 DM translated to in US dollars, in 1951, the data point provided in Ronald’s paper.


    Tradition and custom certainly played a part.  Marine celestial navigation uses printed tables, and has done so since the very earliest books on the topic. The Bygrave was intended for air navigation, therefore, not so tradition bound.


    Your point about the size and weight of a slide rule vs a complete set of printed tables is true.  It begins to fall away when one considers that size and weight  is relative to the number of volumes you carry.  Do you really need to carry the 80 to 89 degree volume with you for a journey within the tropics?  If your vessel truly does navigate from pole to equator, then I suggest that the size and weight of the tables may not be the most important criteria.    


    Best Regards

    Brad Morris



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